A USA Today/Gallup poll released Tuesday found that most Americans considered the killing of al Qaeda leader Abu Musab al-Zarqawi a "major achievement'' and suggested that opinion which has turned steadily against the war remains volatile.

The poll found that 51 percent of Americans still say it was a mistake to go to war in Iraq, a drop from nearly 60 percent at the end of last year. The new poll found that 48 percent believe the war is winnable, up from 39 percent in April.