A top national security adviser to John F. Kerry said yesterday that he made a mistake when he said the Democratic nominee probably would have launched a military invasion to oust Saddam Hussein if he had been president during the past four years.

On Aug. 7, Jamie Rubin told The Washington Post that "in all probability" a Kerry administration would have waged war against Iraq by now if the Massachusetts Democrat were president.

The Bush campaign, eager to portray Kerry as holding the same position as the president after the failure to find weapons of mass destruction, seized on Rubin's comments as evidence that the Republican and Democratic presidential candidates share similar views on the war, in retrospect. On NBC's "Meet the Press" on Sunday, Bush campaign manager Ken Mehlman said the two candidates agreed about "sending our troops to war."

"To the extent that my own comments have contributed to misunderstanding on this issue. . . . I never should have said the phrase 'in all probability' because that's not Kerry's position and he's never said it," Rubin said in a statement. "That was my mistake."

In previous conversations, Rubin said Kerry would have handled the Iraq strategy much differently than Bush from the beginning by allowing U.N. weapons inspectors more time, attracting more allies into the effort and crafting a better postwar plan to stabilize Iraq, among other things. On Aug. 7, when pressed by a reporter about whether Kerry, like Bush, believes he still would have gone to war, Rubin said, "In all probability he would have launched a military invasion with the support of the rest of the world by now."

Some Kerry advisers said Rubin's comments played right into Bush's hands and wanted the record set straight before it exploded into a bigger political issue. Rubin, a State Department official in the Clinton administration who often travels with the candidate, agreed, aides said.

In an interview yesterday, Rubin said it is unknowable whether Kerry would have waged the war. "Bush went to war the wrong way," Rubin said. "What we don't know is what would have happened if a president had gone about it the right way."

Under pressure from Bush, Kerry recently said that, knowing then what he knows now about the lack of chemical, biological and nuclear weapons in Iraq, he still would have voted in 2002 to grant Bush the authority to launch the military attack. "But he never would have gone to war the way George Bush did," Rubin said in the statement. "The Bush Cheney campaign continues to misrepresent John Kerry's position because they are trying to cover President Bush's mistakes, from rushing to war without allies, to not equipping our troops properly, to not having a realistic plan to win the peace."

Jamie Rubin said he misspoke about how the senator would have acted.