What is the definition of an American ally? On an ideological level, an ally is a country that shares America's values, reflects its founding spirit, and resonates with its people's beliefs. Tactically, an ally stands with the United States through multiple conflicts and promotes its global vision. From its location at one strategic crossroads, an ally enhances American intelligence and defense capabilities, and provides ports and training for U.S. forces. Its army is formidable and unequivocally loyal to its democratic government. An ally helps secure America's borders and assists in saving American lives on and off the battlefield. And an ally stimulates the U.S. economy through trade, technological innovation, and job creation.

Few countries fit this description, but Israel is certainly one of them. As U.S. President Barack Obama told a White House gathering, "The United States has no better friend in the world than Israel," a statement reflecting the positions of Democrats and Republicans alike. The importance of the U.S.-Israel alliance has been upheld by successive American administrations and consistently endorsed by lawmakers and military leaders. It should be unimpeachable. But for some it is not.

Rather than viewing Israel as a vital American asset, an increasingly vocal group of foreign-policy analysts insists that support for the Jewish state, including more than $3 billion in annual military aid, is a liability. Advocates of this "realist" school claim that the United States derives little strategic benefit from its association with Israel. The alliance, they assert, arises mainly from lobbyists who place Israel's interests before America's, rather than from a clearheaded assessment of national needs. Realists regard the relationship one-dimensionally -- America gives Israel aid and arms -- and view it as the primary source of Muslim anger at the United States. American and Israeli policies toward the peace process, the realists say, are irreconcilable and incompatible with relations between true allies.

By definition, realists seek a foreign policy immune to public sentiment and special interest groups. In this rarefied view, the preferences of the majority of the American people are immaterial or, worse, self-defeating. This would certainly be the case with the U.S.-Israel alliance, which remains outstandingly popular among Americans. Indeed, a Gallup survey this February showed that two out of three Americans sympathize with Israel. Overall, since the Sept. 11, 2001, attacks, and the wars in Iraq and Afghanistan -- and in spite of Israel's responses to the second intifada and rocket attacks from Lebanon in 2006 and Gaza in 2008 -- support for Israel in the United States has risen, not declined.

The surveys prove that most Americans do not accept the argument that U.S. support for Israel provokes Islamic radicals or do not especially care even if it does. In a Senate hearing last year, Gen. David Petraeus, then head of U.S. Central Command, testified that the Arab-Israeli conflict "challenges … our ability to advance our interests." Critics of the U.S.-Israel relationship seized on the remark as evidence of the alliance's prohibitive costs -- an interpretation Petraeus strenuously rejected -- but the incident wrought no change in popular opinion. In fact, a CNN survey taken later that week showed that eight out of 10 Americans still regarded Israel as an allied or friendly state.

That kind of popular foundation for the Israeli-American alliance is all the more important at a time of great upheaval in the Middle East. As Iran's malign influence spreads and Turkey turns away from the West, Israel's strategic value in the region, both to the United States and to pro-Western Arab governments, will surely increase. Following Hezbollah's recent takeover of Lebanon and the political turmoil in Egypt, Jordan, and the Persian Gulf, Israel is the only Middle Eastern country that is certain to remain stable and unequivocally pro-American. In Israel alone, the United States will not have to choose between upholding its democratic principles and pursuing its vital interests.

And yet, for all their urgency, the close ties between the United States and Israel are hardly new. Their roots extend further than Israel's creation 63 years ago -- rather, they took hold with the Pilgrims' arrival in North America.

THE FORBEARS WHO LANDED on Plymouth Rock in 1620 considered themselves the founders of a "New Israel." Committed to studying Hebrew and bridging the Old and New Canaans -- the Holy Land and America -- they pledged to restore the Jews to their ancestral homeland. Far from peripheral, this "restorationist" movement flourished in colonial America and widely influenced the Founders: Thomas Jefferson and Benjamin Franklin wanted the likeness of Moses leading the children of Israel to serve as the Great Seal of the newly independent United States. John Adams wrote that he "really wish[ed] the Jews again in Judea an independent nation." Abraham Lincoln similarly backed the "noble dream" of a re-created Jewish state, as did Woodrow Wilson, a descendant of Presbyterian ministers, who declared, "To think that I … should be able to help restore the Holy Land to its people."

America's commitment to the Zionist movement to create a Jewish state deeply influenced Harry S. Truman. A fervid Baptist and past member of the restorationist American Christian Palestine Committee, Truman made the United States the first nation to recognize Israel on May 14, 1948. None of the predictions of his realist advisors -- that recognition would trigger an Arab oil embargo, Europe would fall to the Soviet Union, and Israel would turn communist -- became a reality.

The spiritual attachment to the reborn Jewish state has continued to resonate in America, the nation with the highest frequency of church attendance in the industrialized world. Many Americans have also been drawn to the Zionist story of pioneering, hearing in it echoes of their own national narrative. Theodore Roosevelt, who fancied himself a frontiersman, urged that "the Jews be given control of Palestine" and that "a Zionist state around Jerusalem" be created. In a similar vein, Rev. John Haynes Holmes, on talking with Palestinian Jews in 1929, "could think of nothing but the early English settlers who came to the bleak shores of Massachusetts.… Here is the same heroism dedicated to the same ends."

Israel emerged not only as a Jewish and pioneering state, but also as a democracy. In urging Truman to recognize Israel in 1948, White House counsel Clark Clifford argued that "in an area as unstable as the Middle East … it is important to the long-range security of our country … that a nation committed to the democratic system be established, one on which we can rely." The fact that Israelis cherished the same values enshrined in the U.S. Constitution -- free speech and assembly, respect for individual rights, an independent judiciary -- created another layer of affinity with Americans. John F. Kennedy said Israel "carries the shield of democracy and honors the sword of freedom," and Bill Clinton likened Israel to America, "an oasis of liberty, a home to the oppressed and persecuted."

While grappling with the challenges posed by its large Arab minority and, since the Six-Day War, the Palestinians of the West Bank and Gaza, Israel has remained the Middle East's only functional democracy. In a region in which some countries deem homosexuality a capital offense, Israel has hosted gay pride parades and provides shelter for Palestinian homosexuals. And in contrast to the Middle Eastern leaders who hold themselves above the law, a former Israeli president was recently convicted of sexual offenses, the verdict handed down by three judges -- two women and an Arab. Withstanding pressures that have crushed many liberal societies, Israel is one of a handful of states that has never experienced interregna of nondemocratic rule.

Americans intrinsically value these facts -- and that appreciation is reciprocated in Israel. As there are streets in the United States named for David Ben-Gurion and Golda Meir, so, too, can one find Washington and Lincoln streets in Israel. Alone in the Middle East, Israel hosts memorials for Kennedy and Martin Luther King Jr. and two exact replicas of the Liberty Bell.

STILL, ACCEPTING THE DISPASSIONATE definition of America's interests, can Israel realistically be considered an ally? Has it traditionally stood by the United States on issues of world importance and in periods of crisis? Is American support for Israel based on calculated estimates of national interests, or is it the product of pressure from richly funded lobbies?

Israel has always sided with the United States on major global issues. At the United Nations and in other international institutions, the two countries' voting patterns are virtually identical, as are their policies on human rights and international law. Beginning with the Korean conflict and throughout the Cold War, Israel backed America's military engagements, and it has maintained that support in the struggle with radical Islam. In times of danger, especially, Israel has responded to America's needs. Acceding to Richard M. Nixon's request to intervene to save Jordan from Syrian invasion in 1970, Israel mobilized its army, and in 1991, in spite of missile attacks from Iraq, Israel honored George H.W. Bush's request not to retaliate.

Israel is not, of course, situated in some geographical backwater, but at the junction of paramount American interests. Its prominence on the eastern Mediterranean littoral, at the nexus of North Africa and Southwest Asia, has enabled the United States to minimize its military deployments in the area. In the Persian Gulf, by contrast, the absence of a dependable and sturdy ally like Israel has impelled the United States to commit hundreds of thousands of troops and trillions of dollars. Secretary of State Alexander M. Haig's observation 30 years ago still resonates today: "Israel is the largest American aircraft carrier in the world that cannot be sunk, does not carry even one American soldier, and is located in a critical region for American national security."

The strategic synergy between the United States and Israel melds into tactical realities. U.S. troops train with their Israel Defense Forces (IDF) counterparts in aerial combat and special operations. U.S. Navy ships routinely dock in Haifa, Air Force planes refuel at Israeli bases, and the Marines will soon use an Israeli laser to pinpoint targets. In addition to pre-positioning $800 million of arms and medical equipment in Israel, the United States guarantees by law its commitment to preserving Israel's "qualitative military edge," enabling the Jewish state to defend itself, by itself, against Middle Eastern adversaries. As Assistant Secretary of State Andrew Shapiro put it, "Israel is a vital ally and a cornerstone of our regional security commitments," and, accordingly, the two countries have developed the world's most advanced anti-ballistic missiles. Together with the X-band radar station in the Negev -- manned by the first American troops deployed permanently on Israeli soil -- these systems can protect friendly nations from Iranian rockets.

In the intelligence field, in particular, the cooperation between Israel and the United States is vast. According to Maj. Gen. George J. Keegan Jr., former head of U.S. Air Force intelligence, America's military defense capability "owes more to the Israeli intelligence input than it does to any single source of intelligence," the worth of which input, he estimated, exceeds "five CIAs." Israeli and American intelligence agencies continuously exchange information, analyses, and operational experience in counterterrorism and counterproliferation. The U.S. Department of Homeland Security and its Israeli counterpart also share technical know-how in defending ports and terminals from terrorist attacks, countering unconventional weapons and cyberthreats, and combating the drug trade. On the battlefield, Israeli armament protects Bradley and Stryker units from rocket-propelled grenades, while Israeli-made drones and reconnaissance devices surveil hostile territory. U.S. fighter aircraft and helicopters incorporate Israeli concepts and components, as do modern-class U.S. warships. The IDF has furnished U.S. forces with its expertise in the detection and neutralization of improvised explosive devices (IEDs), the largest cause of American casualties.

Israel not only enhances America's defenses -- it also saves American lives. A kibbutz-based company in the Galilee has provided armor for more than 20,000 U.S. military vehicles. "Two days ago, my patrol was ambushed by insurgents using 7.62mm PKM Machineguns," David C. Cox, a platoon sergeant in Iraq, wrote the manufacturers. "None of the rounds penetrated the armor of the vehicle, including one that would have impacted with my head." Marine gunner Joshua Smith, whose Israeli-armored vehicle tripped an IED near Marja, Afghanistan, described how his unit "walked away smiling, laughing, and lived to fight another day." Military medical experts from both countries also meet annually to discuss advances in combat care. One such breakthrough was a coagulating bandage, the brainchild of a Jerusalem start-up company, a million of which have been supplied to U.S. forces (and even applied by a Tucson SWAT team medic to stanch the life-threatening head wound of Rep. Gabrielle Giffords).

In return for its aid to Israel, the United States receives not only an armed but an innovative ally, enhancing America's military edge. That contribution is real and requires no lobbyists to fabricate it. While organizations such as the American Israel Public Affairs Committee (AIPAC) press Israel's case in government and in popular forums, they represent American citizens who view the alliance with Israel as a national American interest. By contrast, the lobbyists for the Arab states and their domestic oil industries represent foreign interests. The hundreds of millions of dollars they have spent on lobbying and public relations campaigns and donations to influential universities such as Harvard and Georgetown have vastly exceeded the budgets of Israel's advocates in Washington.

Pro-Israel groups neither determine America's course in the Middle East nor derail it. Responding to the realists' charge that a so-called Israel Lobby exerts undue influence over American policies, White House Middle East special advisor Dennis Ross wrote in this magazine that "never in the time that I led the American negotiations on the Middle East peace process did we take a step because 'the lobby' wanted us to. Nor did we shy away from one because 'the lobby' opposed it." A 30-year veteran of Middle East diplomacy, Ross concluded that pro-Israel groups "don't distort U.S. policy or undermine American interests."

Understandably, the most sober assessment of American interests is conducted by the U.S. military. The alliance with Israel, Joint Chiefs of Staff Chairman Adm. Mike Mullen told Congress in March, "is of extraordinary value." Israel, according to America's highest-ranking officer, is "absolutely critical" to U.S. national security.

ISRAEL IS AMONG THE FEW COUNTRIES in the world -- and the only Middle Eastern state -- to consistently stand alongside the United States on strategic issues. But the U.S.-Israel relationship is far from one-dimensional. The two countries also cooperate in a broad range of nonmilitary fields -- humanitarian, commercial, and scientific.

Close coordination with the United States enabled Israeli medical teams to arrive first on the scene in earthquake-devastated Haiti. They similarly assisted the victims of Turkish and Indonesian quakes and of famines in Somalia, Mauritania, and Kenya. Together with the U.S. Agency for International Development, Israel's Agency for International Development Cooperation has trained more than 200,000 people from Africa, South America, and Asia in fields as diverse as agrobusiness and ophthalmology. Since 1985, American and Israeli scientists have jointly consulted for developing countries on public health and women's issues.

Israel also assists the American people by stimulating trade, spurring technological innovation, and creating jobs. Despite a population of just 7.7 million people, Israel is America's 20th-largest customer in the world, surpassing Russia and Spain. Warren Buffett's first foreign investment was a $4 billion stake in Iscar, an Israeli tool manufacturer. "I believe in the Israeli market and the Israeli economy," Buffett explained. Between 2000 and 2009, direct U.S. investment in Israel totaled $77.2 billion, while Israelis invested $51.4 billion in the United States. More than 25 years ago, America's very first free trade agreement was signed -- with Israel.

Google, Microsoft, IBM, Intel, AOL, and Motorola are just some of the high-tech companies with major research and development operations in Israel. In addition to providing software and hardware for most American computers and mobile phones, Israel also pioneered the USB flash drive, the ingestible microcamera, advances in drip irrigation, and the portable MRI. Through Better Place, the world's first comprehensive electric-car system, Israel is poised to help Obama achieve his goal of placing 1 million electric vehicles on America's roads by 2015. "It's no exaggeration to say that the kind of innovation going on in Israel is critical to the future of the technology business," observed Microsoft Chairman Bill Gates on a 2005 visit to Israel. After the United States and China, Israel is the most represented country on the Nasdaq stock exchange.

And at a time when American corporations are outsourcing to Asia, Israel is outsourcing to the United States: Tens of thousands of Americans are employed by Teva, the world's leading generic-drug producer, and by dozens of Israeli high-tech, textile, and defense plants throughout the United States. The nearly 6,000 projects mounted by three U.S.-Israel foundations have generated myriad American jobs, as does the $3 billion in American military aid to Israel, $2.25 billion of which is spent in the United States.

IN SPITE OF THE OVERWHELMING ADVANTAGES of the U.S.-Israel alliance, the realists still insist that it stokes Muslim rage and renders Americans more vulnerable to terrorism. To substantiate their claim, the realists quote Osama bin Laden as well as the state-controlled Middle Eastern media. But bin Laden initially justified his attacks on America's profligacy and only later, after his setbacks in Afghanistan, linked them to Israel. An influential Saudi Wahhabi book published online describes the United States as "the source of evil, moral corruption, oppression, despotism, and aggression … in the world" and makes no mention of Israel. Neither do recently published diplomatic papers from the Middle East or most of the demonstrations that have convulsed the region.

The official U.S. documents released by WikiLeaks show that Arab rulers are not preoccupied with Israel but with the perils posed by Iran. One report recounted Saudi King Abdullah urging the United States to "cut off the head of the snake" -- Iran -- and to attack the country's nuclear facilities at once. Bahrain's king warned that "the danger of letting [the Iranian nuclear program] go on is greater than the danger of stopping it." The word "Israel" does not appear.

Middle Eastern populations, meanwhile, have shown that they, too, are less concerned with Israel than with urgent issues at home. When able to express themselves freely, they have preferred to focus on political rights and economic opportunity. Conspicuously absent from the protests that swept the region in 2011 were burning Israeli -- or American -- flags or any reference to the U.S.-Israel relationship.

Although emerging Arab governments might in the future -- as in the past -- seek to gain legitimacy by harnessing anti-Israeli sentiment, the claim that American support for the Jewish state axiomatically translates into anti-Americanism in the Middle East is no longer sustainable.

Israel is America's staunchest ally in the Middle East, but even the warmest friendships are never disagreement-free. This was certainly the case with the Anglo-American relationship during World War II, modern history's most celebrated alliance, but one that was riven by disputes over military planning and postwar arrangements.

The United States and Israel could not, therefore, realistically be expected to concur on all of the Middle East's labyrinthine issues. Ronald Reagan, for example, condemned Israel's attack on an Iraqi nuclear reactor in 1981, and Israel objected to his sale of advanced jets to Saudi Arabia.

The realists say that the gaps between Israeli and American policies on the peace process are unbridgeable. The United States, they maintain, is committed to creating a Palestinian state in the West Bank and Gaza, with East Jerusalem as its capital. Israel allegedly opposes these goals and thwarts them by building in those areas.

But historically, progress in the peace process has been directly related to the strengthening of America's alliance with Israel. That bond convinced Arab rulers that they had no conventional military option against Israel and fortified Israelis to make the concessions necessary for peace. American security assurances -- including guarantees of continued oil supplies from Sinai and the replacement of evacuated air bases -- enabled Israel to withdraw from an area three times its size and to conclude the 1979 peace treaty with Egypt.

The realists ignore or dismiss this linkage, as they do Israel's record of seeking peace. In the euphoric aftermath of the Six-Day War, Israeli leaders offered to create a West Bank Palestinian state, but Palestinian leaders rejected the plan. Israel in 2000 offered the Palestinians sovereignty over virtually the entire West Bank, all of Gaza, and part of Jerusalem, but the Palestinians refused the deal and instead killed more than 1,000 Israelis in terrorist attacks. In 2005, Israel provided the Palestinians with the chance to create a peaceful prototype in Gaza, but it quickly devolved into a launching pad for thousands of rockets. In spite of these traumas, a significant majority of Israelis -- 66 percent, when recently asked by the Tel Aviv University Peace Index -- still favor the two-state solution, testifying to their commitment to peace.

Settlements, meanwhile, have never been the impediment to peace. They did not preclude the signing of the Egyptian and Jordanian treaties or 16 years of Israeli-Palestinian negotiations. Israel uprooted all 21 settlements in Gaza and received war, not peace. Later, Prime Minister Benjamin Netanyahu froze West Bank construction for an unprecedented 10 months, but the Palestinians still refused to negotiate. Internal Palestinian documents published recently by Al Jazeera reveal that Palestinian negotiators in 2008 were willing to concede the bulk of the Israeli communities in the West Bank, as well as most of the Jewish neighborhoods built over the 1967 line in Jerusalem, as part of a peace arrangement. Israeli leaders were ready to sign; the Palestinians again walked away.

Blind to Israel's record of peacemaking, the realists also overlook the broad confluence of American and Israeli policies toward the process. Both insist that there is no alternative to direct negotiations and no solution to the conflict other than two states for two peoples. They understand that the Palestinian state, situated opposite Israel's narrowest and most populous area, will have to be demilitarized and that Israel will require detailed security guarantees. And they agree that any peace treaty must provide for mutual recognition between the nation-states of the Jewish and Palestinian peoples, signifying an end to all claims.

American and Israeli positions also dovetail on the most monumental -- and potentially divisive -- Middle Eastern issue: Iran. A nuclear-armed Iran, both countries hold, will imperil every pro-Western Middle Eastern state and ignite a nuclear arms race in an inherently unstable region. The United States and Israel have promoted international sanctions designed to prevent Iran from developing nuclear weapons, while keeping all options on the table. Americans know that, at a time of transformation in the Middle East balance of power, Israel remains the region's only credible foil to Iran.

Ultimately, the litmus test of any alliance is not whether the partners agree on every issue, but rather the ways they deal with discord. During World War II, the United States and Britain bridged their differences and achieved victory. America and Israel have similarly worked through their differences and are together striving for a different triumph -- peace.

WHO ARE AMERICA'S ALLIES in the world today? Which countries are both capable and willing to advance American interests? A truly realist assessment would strive to answer these questions and fairly weigh Israel's worth.

In the Middle East, every Arab or non-Arab Muslim country has at times vacillated in its support of the United States or adopted anti-American positions. Some regimes have also placed oil embargoes on Americans and bankrolled their enemies. Although democratic governments may yet emerge in some Middle Eastern states, autocracy, monarchy, and dictatorship remain the region's norm. And even elected representatives can be profoundly hostile to the United States, as in Iran, Lebanon, and Gaza.

Elsewhere in the world, new powers are arising, but few are likely to act as American allies in the realist sense. Others will be robust competitors. America's European allies, meanwhile, are further restricting the conditions under which their forces fight and drastically slashing defense budgets. British military sources estimate that troop numbers will soon be reduced to 80,000, leaving Britain with its smallest army since the 1820s. With similar cuts expected in Germany, Italy, and France, the United States will become harder-pressed to rely on European support during crises."[W]e won't be able to defend the security on which our democratic societies … depend," NATO Secretary-General Anders Fogh Rasmussen has warned. "We risk a Europe increasingly adrift from the United States."

Israel is the only Middle Eastern state never to oppose America on major international issues. Its fundamental interests, like its values, are America's. For the price of annual military aid equaling roughly half the cost of one Zumwalt-class destroyer, the United States helps maintain the military might of one of the few nations actively contributing to America's defense. It reinforces the only country capable of deterring Hamas and Hezbollah and impeding the spread of Iranian hegemony. According to published sources, the Israel Defense Forces is larger than the French and British armies combined. The IDF is superbly trained and, when summoned, capable of mobilizing within hours.

These benefits of the U.S.-Israel relationship are of incalculable value to the United States, far outweighing any price. Americans know that Israelis have always stood by them, ready to share technology, intelligence, and innovation -- ready to aid them in conflict and to make the painful sacrifices for peace. Israel may be one of a handful of countries that fully fits the definition of ally, but its willingness to support the United States unwaveringly makes it the partner par excellence, America's ultimate ally.