Most Americans want Congress to more actively support President Bush's Middle East policies, but an equally large majority still expects Bush to ask lawmakers before using military force to drive Iraq out of Kuwait, according to a new Washington Post-ABC News Poll.

The survey also found growing support for Bush's handling of the Persian Gulf crisis, as well as continued strong backing for overall U.S. policy objectives in the region. The survey found that more than six out of 10 Americans support war with Iraq if Iraqi President Saddam Hussein does not withdraw his troops from Kuwait by next Tuesday's U.N. deadline.

But once the shooting starts, public support for a war with Iraq may quickly evaporate in the face of even modest U.S. casualties, according to the poll.

Many Americans remain hopeful that the crisis can be resolved without a war. Nine out of 10 said they supported Bush's decision to have Secretary of State James A. Baker III meet with Iraqi Foreign Minister Tariq Aziz in Geneva Wednesday. And about half of those questioned said that U.S.-Iraqi talks will lead to a peaceful end to the five-month crisis.

Interviews with a national sampling of 1,057 randomly selected adults Friday through Sunday found broad support for the administration's handling of the crisis and growing acceptance of a military solution. Margin of sampling error for the overall results is plus or minus 3 percentage points.

According to the survey, 67 percent of those questioned said they approved of the way Bush was handling the situation in the gulf -- the highest level in a Post-ABC News survey since early September.

Although a growing majority believes force should be used to drive Iraq out of Kuwait, the latest poll also found that it may be difficult to sustain public support for the war effort if the conflict results in even modest casualties.

Support for the war option dropped from 63 percent to 44 percent when respondents were asked whether they would back a war after next Tuesday if it "meant 1,000 Americans troops would be killed in the fighting." And barely a third -- 35 percent -- said they would support a war in which 10,000 U.S. troops would die.

Seven out of 10 Americans continue to believe that the United States will become involved in a war with Iraq. But an equally large majority -- 67 percent -- believes it "would be a relatively short war, lasting a few weeks or months." Only 29 percent predicted a long war lasting a year or more.

Perceptions of the length of a possible conflict are closely linked to attitudes on the war option, the survey found.

Among those who believe it would be short, 74 percent supported going to war sometime after the U.N. deadline. But among those who thought the war would continue longer than a few months, just 38 percent favored the war option.

As Congress prepares to debate U.S. policy in the gulf, nearly seven out of 10 adults said they want lawmakers to be "more actively supporting" Bush policies. One in five said Congress should more actively oppose the administration.

While support remains high for involving Congress in any war decision, the survey suggests that a growing minority believes that Bush can act without formal support from Capitol Hill.

Of those surveyed, 66 percent, including majorities of both Republicans and Democrats, said they want Bush to ask permission from Congress before launching any attack.

Last month, 78 percent wanted Bush to go to Congress first.

Senior polling analyst Sharon Warden contributed to this report.