Four in 10 adults still think the U.S. found active weapons of mass destruction in Iraq, according to a new poll. 

The Fairleigh Dickinson University's Public Mind poll finds that 42 percent of the public believes U.S. forces found active WMDs in Iraq, even though they, in fact, did not. 

More than half of Republicans think WMDs were found during the U.S. invasion of Iraq under President George W. Bush, with 51 percent saying it is "probably" or "definitely" true (14 percent said "definitely). 

The Bush administration used the threat of WMDs in Iraq to help justify the invasion. 

Even among Democrats, 32 percent say that WMDS were found. 

The polling center notes that part of the confusion could be a New York Times story in October that revealed that U.S. soldiers had been exposed to old, degraded chemical weapons in Iraq. That story made clear that U.S. forces did not find an active program.

The poll also finds that 19 percent of the public thinks that President Obama is not a U.S. citizen, despite the release of his long form birth certificate proving that he is. That includes 34 percent of Republicans, 22 percent of independents and 7 percent of Democrats. 

Thirteen percent of the public thinks that recent mistakes by the Secret Service are because of a deliberate attempt to leave the president unprotected, a figure that rises to 20 percent among nonwhites.