President Obama's close friends and key advisers have helped him shape the toughest line against the continued expansion of Israeli settlements since the administration of President Jimmy Carter.

The result has been a confrontation with Israeli Prime Minister Binyamin Netanyahu that has surprised the Israeli government and many analysts. Netanyahu is preparing to make a major speech tomorrow in which he is expected to respond to the new American pressure.

Obama's aides are steeped in the complex issues of the Israeli-Palestinian conflict and in U.S. attempts to resolve it. Many of them bring long memories of difficult dealings with Netanyahu when he served as prime minister more than a decade ago.

Obama's advisers have concluded that peace in the Middle East will require an end to the construction of new Israeli homes on occupied territory that Palestinians claim for a new state. In his speech in Cairo this month, Obama made it clear he had reached the same conclusion. Forcing Netanyahu to relent on settlements would offer the U.S. administration leverage in persuading Arab states to engage in peace talks.

"There is a strong consensus in the White House that the status quo is not going to produce progress and that the moment could slip away here for a real, just, lasting peace that would bring Israel the security it needs," said David Axelrod, one of Obama's top advisers.

But several senior White House officials described the president's views on Israeli settlements as years old and not the product of recent events or discussions. "It would be a mistake to suggest that anyone led him to this position," a senior adviser said. "It's one that he generated himself."

In Chicago, long before becoming president, Obama's closest confidants included staunch supporters of Israel whose tough views on the need to stop settlements mirror his current public position. Abner Mikva, an Obama mentor and former law professor, was one of them.

"There has to be realistic talks about how the two states will get along together," Mikva said, describing Obama's thinking on the subject of Middle East peace before being elected to the U.S. Senate. "You can't do that if one state, as you're talking, is picking up more land."

White House aides say the president has been careful to insist that Palestinians must also act to fulfill their responsibilities, such as bolstering security and ending anti-Israeli incitement.

"It is a sign of neither courage nor power to shoot rockets at sleeping children, or to blow up old women on a bus. That is not how moral authority is claimed; that is how it is surrendered," Obama said in the Cairo speech.

But his recent language about settlements is the starkest of any U.S. president in three decades, and tougher than most of his public rhetoric since emerging on the national scene.

One of the president's close friends in Chicago, the late Rabbi Arnold Wolf, wrote last year of his disappointment that Obama had often publicly softened his private positions.

"For my part, I've sometimes found Obama too cautious on Israel," said Wolf, who in 1973 co-founded an organization that advocated creating a Palestinian state. "He, like all our politicians, knows he mustn't stray too far from the conventional line, and that can be disappointing. But unlike anyone else on the stump, Obama has also made it clear that he'll broaden the dialogue."

In June 2005, during a Senate Foreign Relations Committee hearing on Israel's withdrawal from the Gaza Strip, then-Sen. Obama took note of domestic politics within Israel, saying, "There are important and difficult political problems within Israel with respect to the settlers."

By March 2007, as he was beginning his presidential quest, Obama hinted at his feelings about the settlements in a speech before the leading pro-Israel organization, the American Israel Political Affairs Committee. He referred to "stones" that will "be heavy and tough for Israel to carry."

In June 2008, while on the verge of securing the Democratic nomination, Obama went further. He told the same group that Israel could advance the cause of peace by refraining "from building new settlements, as it agreed to do with the Bush administration."

Both those references to settlement were mild compared with his speech in Cairo. The president declared that "the United States does not accept the legitimacy of continued Israeli settlements. This construction violates previous agreements and undermines efforts to achieve peace. It is time for these settlements to stop."

Obama's Middle East advisers share similar views about the need to rein in the settlements, as agreed to in the 2003 "road map" to peace.

White House Chief of Staff Rahm Emanuel worked in the Clinton White House when Netanyahu reneged on an understanding to stop the growth of settlements. As a member of Congress, Emanuel was one of only two Jewish lawmakers to co-sponsor a resolution supporting a peace plan that would have abandoned to the Palestinians one of the West Bank's largest settlements -- Ariel, with about 40,000 settlers.

Former senator George J. Mitchell, the president's special envoy for Middle East peace, headed the commission in 2001 that first recommended a settlement freeze. "Stop construction, stop building and expanding," Mitchell declared during a television interview seven years ago.

As a special envoy for then-Secretary of State Condoleezza Rice in 2008, James L. Jones -- now Obama's national security adviser -- examined the security issues involved in creating a Palestinian state. The Israeli media reported that he drafted a report, never released by the Bush administration, that was highly critical of Israel's policies in the West Bank.

Politically, there is little danger for the president in confronting Israel, especially if it leads to a peace deal. Polls suggest that settlements hold little appeal to many American Jews and have rapidly decreasing support in Congress.

"They made a political calculation that this is something they could sell on Capitol Hill," said Samuel Lewis, former U.S. ambassador to Israel. "It will divide the Israelis and put Netanyahu on the defensive."

Within the Obama White House, discussions leading up to the Cairo speech focused more on the ramifications of a tougher stand in the Arab and Israeli communities, officials said. The discussions were informed by polling in Israel, which indicates that many Israelis view the settlers as a fringe group and do not support settlement expansion.

"Was there an awareness that that point and others in the speech, that there would be some churning in the commentary or so on?" one top Obama adviser said. "There was. But he viewed that as a necessary part of moving the process forward."

Early evidence of that view was captured on tape during a private gathering in Cleveland in 2008. Obama challenged Jewish groups to allow for greater debate on Israeli actions and not demand what he called a "pro-Likud approach," referring to Netanyahu's party.

"This is where I get to be honest, and I hope I'm not out of school here," he said in a transcript published by JTA, a news service on Jewish issues. "I think there is a strain within the pro-Israel community that says unless you adopt an unwavering pro-Likud approach to Israel that you're anti-Israel. . . . If we cannot have an honest dialogue about how do we achieve these goals, then we're not going to make progress."