There are enormous differences between the war in Iraq and the one in Vietnam that defined a generation. The current conflict hasn't lasted as long, taken nearly as many American lives or sparked the sort of massive protests that became common in the '60s and '70s.

But when it comes to public opinion, Americans' attitudes toward Iraq and the proper course ahead are remarkably similar to public attitudes toward Vietnam in the summer of 1970, a pivotal year in that conflict and a time of enormous domestic unrest.

Some political scientists and Vietnam War historians predict the Iraq war, like the one in Southeast Asia a quarter-century ago, will shape American attitudes long after it's over.

"This war is probably a really big deal historically in terms of America's perspective on the world," says John Mueller, a political scientist at Ohio State University. "What you're going to get after this is 'We don't want to do that again — No more Iraqs' just as after Vietnam the syndrome was 'No more Vietnams.' "

A USA TODAY/CNN/Gallup Poll taken Friday through Sunday found that just more than half of those surveyed wanted to withdraw U.S. troops from Iraq within the next 12 months. In a Gallup Poll in July-August 1970, just less than half wanted to withdraw U.S. troops from Vietnam within 12 months.

In both surveys, about one-third supported withdrawing troops over as many years as needed, and about one in 10 wanted to send more troops.