Last week Iran sent a high-level envoy, Saeed Jalili, on a particularly controversial public-relations tour to Lebanon and Syria, the most explosive corner of the region. After ruffling feathers during a Beirut stopover, Mr. Jalili traveled to Damascus to meet with President Bashar al- Assad, where he declared the ties between Iran, Syria, and Hezbollah to be an “axis of resistance.”

Jalili is an iconic figure, whose position as the head of Iran’s Supreme National Security Council also affords him the role of chief negotiator for Iran’s contentious nuclear program. Amidst a deadlock in negotiations and a rehashing of threatening rhetoric, Jalili’s visit was meant to remind the Israelis that Iran’s proxies on Israel’s northern doorstep remain ready and willing to plunge the region into chaos if Israel strikes Iran’s nuclear facilities.

It appears however, that Iran’s allies in the eastern Mediterranean may not be as keen about going to war for the ayatollahs as Tehran would like – and the Israelis know it.

The threat of a simultaneous war with Hezbollah, Syria, and Gaza militants is the primary concern for the Israeli security establishment as it weighs a strike on Iran. Dubbed “the long arm of Iran” at the Israel Defense ForcesI headquarters, Hezbollah in Lebanon is said to possess more than 70,000 missiles that can strike as far south as Israel’s nuclear reactor near the city of Dimona – nearly 140 miles from the Lebanese border.

Combine this arsenal with the more than 10,000 rockets and missiles in the Gaza Strip and with Mr. Assad’s chemical weapons, and the threat to Israel’s home front is the most formidable since the 1973 Yom Kippur War when Egypt and Syria attacked Israel.

And yet, Israeli leaders seem content to shrug off this threat. On two recent occasions, Defense Minister Ehud Barak boldly estimated that Israel would sustain 300 to 500 casualties in a conflict with Iran and its proxies. Such an estimate suggests that Mr. Barak himself does not believe that Israeli cities will bear the full brunt of Iran’s “long arm” as a consequence to a strike.

Prime Minister Benjamin Netanyahu also dismissed the danger of regional conflict by stating that these threats to the home front are “dwarfed” by a nuclear Iran.

Judging from their statements, Hezbollah leaders aren’t so sure they want to enter into a conflict with Israel at Iran’s behest. In February 2012, Hezbollah leader Hassan Nasrallah said, “I tell you that the Iranian leadership will not ask Hezbollah to do anything. On that day, we will sit, think and decide what we will do.”

Mr. Nasrallah’s hesitation is understandable. Entering into broad conflict with Israel would result in even greater destruction to Lebanon than in the 2006 Lebanon war. This time, Hezbollah would be unable to replenish its stockpiles or rebuild destroyed villages so easily. Nasrallah’s guarantor in Damascus is on his last legs, while his primary bankrollers in Tehran have already cut funding to the group as a result of sanctions and diversion of resources to Syria.

Further, entering into a conflict with Israel would likely severely damage Nasrallah’s private militia, benefitting his sectarian rivals by stripping him of the only warranty of his political hegemony in Lebanon.

Next door in Syria, Assad faces similar concerns. A conflict with Israel could compromise his military advantage over an increasingly powerful rebel army, including the chemical weapons stockpiles so necessary in securing the protection of Alawite enclaves as the civil war intensifies.

Meanwhile, Iran’s relationship with militant groups in the Gaza Strip has witnessed a dramatic shift in the midst of the Arab Spring. As Mahmoud al-Zahar, a senior leader of Hamas in Gaza, put it in March, “If Israel attacks us, we will respond. If they don’t, we will not get involved in any regional conflict” – though an Iranian report had him directly contradicting that statement and promising to retaliate “with utmost power.”

Regardless of how the Iranian media may present Mr. Zahar, Hamas seems to be returning to its Sunni loyalties, cozying up to Egypt’s Muslim Brotherhood, and away from Iran. Further, the trauma from the 2009 armed conflict with Israel in Gaza, known as Operation Cast Lead, continues to keep rockets off the Hamas launching pad. The sole mission of a  300-strong guerrilla force employed by Hamas is to impede rocket attacks by smaller splinter groups. Such attacks have recently flared.

Despite the weakened state of Iran’s proxies, an Israeli strike on the ayatollah’s nuclear program will not be without consequence. Hezbollah and splinter Gaza militant groups are likely to attack Israel in a display of their solidarity, albeit only in a limited effort. Judging from past flare-ups, these groups understand Israel’s red lines, knowing exactly what ranges and what rates in which to fire their rockets while avoiding drawing the Israel into a confrontation which could compromise their grip on power.

Netanyahu seems willing to go down in history as the prime minister who saved Isrel from a nuclear Iran. And he’s counting on minimal retaliation from Iran’s proxies if Israel strikes first. But as Barbara Tuchman, the World War I historian, once said, “war is the unfolding of miscalculations.”