Additional information For complete text of the State of the Union address: www.whitehouse.gov/

WASHINGTON — President Bush challenged a hesitant Congress on Wednesday to "strengthen and save" Social Security, saying the nation's costliest social program was headed for bankruptcy unless changed. Bush's plan would cut guaranteed retirement benefits for younger Americans but would not affect checks for people now 55 and older.

Bush, in his State of the Union address, pledged to work with Congress "to find the most effective combination of reforms," although he has ruled out some remedies such as raising Social Security taxes.

Democrats said that Bush's proposal to divert Social Security revenues into private investment accounts was dangerous and that there were better ways to fix the program, the 70-year-old centerpiece of the New Deal.

Republicans stood and cheered when Bush urged lawmakers to approve "voluntary personal retirement accounts." Democrats sat in stony silence, underscoring the partisan divide on an issue likely to dominate the year in Congress. Democrats also groaned and grumbled when Bush said Social Security would require drastically higher taxes, massive new borrowing or severe benefit cuts unless the system is changed.

Bush's 53-minute speech spanned problems at home and abroad, but it was the first State of the Union address since the Sept. 11, 2001, terrorist attacks that focused most heavily on domestic issues. Despite Democrats' criticism, he offered no hint of a timetable for a troop withdrawal from Iraq.

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

Bush pledged to confront regimes that promote terror and pursue weapons of mass destruction, and singled out Syria and Iran. Returning to his inaugural address theme of spreading democracy, Bush hailed the success of Sunday's elections in Iraq.