Most Americans favor using nuclear weapons against Iraq if Saddam Hussein attacks U.S. military forces with chemical or biological weapons in a war that the public believes is virtually inevitable, according to a Washington Post-ABC News poll.

The survey found that six in 10 Americans favored a nuclear response if Saddam orders use of chemical or biological weapons on U.S. troops. Slightly more than a third — 37 percent — were opposed. Nearly nine in 10 Americans said the United States is headed for war with Iraq, which most Americans believe possesses weapons of mass destruction.

But the survey also found that 58 percent of those interviewed would like to see President Bush present more evidence explaining why the United States should use military force to topple the Iraqi leader, up from 50 percent in September. And while most Americans view Iraq as a threat, fewer than half said it posed an immediate danger to this country.

That finding and others suggest Bush may be moving faster toward war than the public would prefer. At the time Americans are becoming more certain that war will break out, the survey found they also are growing more wary of the president and his motives for pressing to move quickly with military force against Iraq.

More than half — 54 percent — feared Bush would act too quickly to use force. And an even larger majority — 58 percent — opposed taking military action against Iraq without the support of the United Nations.

A total of 1,209 randomly selected adults were interviewed Dec. 12-15 for this survey. Margin of sampling error for the overall results is plus or minus 3 percentage points.