President Bush on Sunday dismissed the rejection of Iraq's new draft constitution by Sunni negotiators as the opinion of a few, expressing confidence that the failure to secure backing from all the country's ethnic and political groups won't derail a transition to democracy.

Bush also predicted an increase in insurgent attacks that will be "more desperate, more despicable and more vicious" leading up to the Oct. 15 referendum in which Iraqis will vote on whether to accept or reject the document. He said the United States would help assure success for the Iraqis, but didn't say precisely how.

"We are determined to see the Iraqis fully secure their democratic gains," Bush told reporters in a brief statement delivered in a helicopter hangar on his ranch. "This course is going to be difficult, largely because the terrorists have chosen to wage war against a future of freedom."

The president, who spoke briefly to reporters from a helicopter hangar on his ranch, did not take questions.

Afterward, his spokesman, Scott McClellan was asked what the administration plans to do to see the constitution approved despite the Sunni rejection. He said, for instance, that not all Sunnis (search) on the panel that wrote the constitution took issue with the final product.

"This is an Iraqi-run process," he said. "This is democracy at work, and we have great confidence in the Iraqi people to chart a democratic future based on their own traditions and culture."

Sen. Joe Biden, D-Del., was less optimistic.

"At the end of the day, if the Sunnis and that entire portion of the country opts out of this process, that's a formula for civil war," he said on ABC's "This Week."

"It's just too hard to tell how much of this is posturing at this point and how much of this is going to result in people taking up arms. The administration is spinning it by suggesting that ... there's a lot of Sunnis that are really for this -- they're just afraid to speak up and say anything now."

After Iraqi negotiators finished the draft Sunday, it was read to the legislature but lawmakers adjourned without voting.

The proposed constitution included last-minute changes aimed at easing Sunni concerns. But those concerns were not overcome and 15-member negotiating Sunni negotiating team rejected the constitution as "illegitimate," raising serious concerns about the outcome of the October referendum.

If two-thirds of voters in any three provinces reject the charter, the constitution will be defeated. Sunnis, though a minority in Iraq's overall population of 27 million, have the majority in at least four provinces.

The United States, in hopes of producing a constitution with widespread support that would take the steam out of the violent Sunni-led insurgency, worked furiously to avert this result to no avail. Bush even intervened personally earlier in the week.

But the president sought to dispel any fallout from the failure to meet U.S. goals.

"Of course, there's disagreement," he said. "We're watching a political process unfold, a process that has encouraged debate and compromise -- a constitution that was written in a society in which people recognize that there had to be give and take."

The U.S. Constitution, he noted, was not unanimously received.

"Some Sunnis have expressed reservations about various provisions of the constitution," Bush said. "There are strong beliefs among other Sunnis that this constitution is good for all Iraqis, and that it adequately reflects compromises suitable to all groups."

The U.S. ambassador to Iraq, Zalmay Khalilzad (search), said he expects Sunnis to eventually join the political process and said their support represents the best hope for "a joint road map for the future of Iraq."

"Not everyone loves every article of this document, not everyone is totally satisfied, but there is enough in this constitution that meets the basic needs of all communities and for Iraq to move forward," Khalilzad said on NBC's "Meet the Press."

But reflecting the turmoil in Iraq over the document's drafting, he was already talking about the need for changes.

Despite the problems, Bush said the Iraqi people "have once again demonstrated to the world that they are up to the historic challenges before them.

"Their example is an inspiration to all who share the universal values of freedom, democracy and the rule of law," he said. "This is a document of which the Iraqis and the rest of the world can be proud."

As Bush attempted to put the best face on the developments in Iraq, just down the road anti-war activists who have been camped near his ranch for most of the month were holding a large demonstration against his anti-war policies. The Rev. Al Sharpton was the featured speaker at a clergy service and bell-ringing that remembered soldiers killed in the war and called upon the president to bring troops home from Iraq."