Saying "now is precisely the right time to launch" negotiations between the Israelis and Palestinians, President Bush told the Annapolis peace conference Tuesday that the choice now is stark: between peace based on two democratic states, and extremism and violence.

Mr. Bush was host to only the second occasion in history where Arabs and Israelis have formally sat together to discuss Middle East peace. He said peace can be achieved only if all the interested parties – the Israelis and Palestinians, as well as the Arab states and the international community – play their part.

But Bush emphasized that a successful peace accord would depend on whether the two main parties – Israel and a yet-to-be-created Palestine – are determined to get there. "The United States is proud to host this meeting," Bush said, "but in the end, [success] depends on the Israelis and Palestinians themselves. We cannot achieve [peace] for them."

Flanked by Israeli Prime Minister Ehud Olmert and Palestinian President Mahmoud Abbas, Bush read what he called an "agreed statement" of "joint understanding" that laid out obligations for both sides. Seeking to build a certain momentum, Bush announced that the two sides would begin regular bilateral negotiations on Dec. 12. He said they would try to reach an accord by the end of next year.

Playing down any direct role for the US or any other outside party, Bush spoke of a "support role" for such parties. That tone suggests Annapolis could be the high-water mark for the president's involvement in the peace process if the Israelis and Palestinians are unable to push forward on their own.

It may or may not be an irony of history that the first meeting drawing Arabs and Israelis to the same table was the Madrid conference in 1991 during the presidency of George H.W. Bush.

The current president squelched the idea of a conference when former Secretary of State Colin Powell proposed one in 2002. Now, Stephen Zunes, a Middle East expert at the University of San Francisco, suspects that Bush's reasons for blessing the idea have more to do with generally addressing conditions in the Middle East region.

"It's mainly to show the Arab world that despite the mess in Iraq and the threats against Iran, we're still concerned about the Palestinians and really do want to do something about it," he says. "But substantively, I'm hard pressed to see what's coming out of this," he adds – in part because he doesn't see Bush or his administration stepping in to really push the two sides to hard bargaining.

That conclusion is bolstered by statements from the president's own advisers. "The president's view has always been that we are not going to impose a negotiation on the parties and we're not going to impose a timetable on the parties just to reflect American politics or anything else," said Stephen Hadley, national security adviser to Bush, in comments to the press on the summit's eve.

Still, the president's embrace of the conference idea suggests that he believes the door is now open to try for peace in a way that it wasn't in 2002.

What has changed for Bush? The leadership of the principal parties, in particular that of the Palestinian Authority. Bush repeated Monday that Palestinian President Mahmoud Abbas is a leader he can work with.

In addition, the president said Tuesday that now is the time for peace because of the crossroads at which the region stands. "A battle is under way for the future of the Middle East," he said.

Another important change is that Bush was pressed to accept holding a peace conference by Secretary of State Condoleezza Rice, a Bush confidante and key foreign-policy adviser (but who opposed the conference idea when Mr. Powell proposed it).

Hadley suggests that Bush, while not adopting a hands-on approach, will continue to offer the big picture of what an Israeli-Palestinian accord must look like and what it can mean for the region and the world – as he did with his June 2002 speech that set him on record as supporting a two-state solution. "He will make very clear that this [bilateral] effort has his support and is a top priority for the remaining time in his second term," Hadley says.

White House officials continue to hammer at what this is not for the president: It is not Bush suddenly getting President Clinton's religion on presidential Mideast diplomacy, and it is not Bush's dive into shuttle diplomacy.

"The notion that somehow the key to success is simply for the United States to lean on one side or another and jam a settlement through is just not what history has suggested," Hadley says.

But some experts believe that the US, including the president, will at some point have to get into the talks and butt heads – squeezing unpalatable compromises out of each side – if negotiations are to succeed, especially by the end of 2008.

"Saying the two sides have to work it out between themselves isn't a recipe for success and isn't likely to move things very far," says Mr. Zunes of the University of San Francisco. For one thing, he says, the "asymmetry of power" between the two parties doesn't augur well for the two making progress on their own.

Zunes adds that if Bush is "unable to push the Palestinians and unwilling to push the Israelis," it's difficult to see how much has changed from the start of Bush's presidency.

"It's significant that Bush is the first president to use the word 'Palestine' in talking about creation of a Palestinian state," Zunes says, "but at some point this has to be about getting beyond statements."