A poll shows a big swing in U.S. public opinion against the war in Iraq this month, with a majority of Americans now saying they believe the United States made a mistake in sending troops to Iraq.

Fifty-four percent of those who took part in a survey conducted by the Gallup polling organization for CNN television and the newspaper USA Today say U.S. military involvement in Iraq was a mistake -- the first time that opinion has been expressed by a majority of Americans.

The Gallup poll asked the same question on six earlier occasions since March 2003. During the first days of the war, 75 percent of Americans said they felt U.S. military action was the right course; since October, between 40 and 44 percent of those polled have said the U.S. military involvement was a mistake.