WASHINGTON (AP) - At the dawn of a second term, President Bush is campaigning again, this time for changes in Social Security that would combine reduced government benefits for younger workers with ''a chance to build a nest egg'' through personal accounts.

''We must make Social Security permanently sound, not leave that task for another day,'' Bush told Congress Wednesday night in a State of the Union address that elicited applause from Republicans and audible grumbles from Democrats in the audience.

With success in Congress far from assured, the president chose to follow up the prime time televised speech with trips over two days to four states. Each is represented in the Senate by at least one Democrat the administration hopes to sway on Social Security.

Bush's first stop was North Dakota, which he won heavily in last fall's election. Even so, early indications were not so positive this time.

''He's saying we've got to take more money out of Social Security to start private accounts and borrow the money,'' said Sen. Kent Conrad, D-N.D., a target of Bush's travels. ''I just think it's very unwise.''

Other Democrats said Bush's program could reduce guaranteed government benefits for younger Americans by 40 percent.

Bush offered no information on that point Wednesday night as he outlined his plans in broad strokes. Aides said that by leaving many key details vague, he intended to give GOP congressional leaders room to piece together legislation that can command a majority.

He laid down a few markers, though, saying he will not agree to increase payroll taxes and wants provisions to keep lower-income Americans above the poverty line during retirement.

''We must guarantee that there is no change'' in current or promised benefits for anyone age 55 and older, he said in a move to neutralize opposition from older Americans.

In a 53-minute speech, Bush also blended the conservative with the compassionate, and gave no ground on his policy on the war in Iraq in which more than 1,400 American forces have died.

He renewed his call for a constitutional amendment banning gay marriage and announced an increase in the use of DNA evidence to prevent wrongful convictions. ''Soon I will send Congress a proposal to fund special training for defense counsel in capital cases,'' he added.

In an echo of his inaugural address pledge to promote freedom overseas, he called on the government of Iran to ''end its support for terror. And to the Iranian people, I say tonight: As you stand for your own liberty, America stands with you.''

The longest applause was when Bush recognized Janet and Bill Norwood, the parents Marine Sgt. Byron Norwood of Pflugerville, Texas, who was killed in the assault of Fallujah. In an emotional and symbolic moment, Mrs. Norwood and Safia Taleb al-Suhail, leader of the Iraqi Women's Political Council, held each other in a long embrace.