Iowa Senate candidate Joni Ernst (R) still believes Iraq likely had weapons of mass destruction before the U.S. invaded.
There has been no evidence that Iraq had weapons of mass destruction, a major justification the Bush administration used for the invasion in 2003.
Ernst later sought to clarify her comments.
"I did not mean to suggest that Iraq had WMD at the time of invasion. It is clear they did not. What I was trying to say was that Iraq had had WMD in their past, and had even used them. My point was that we don't know exactly what happened to those weapons," she told The Hill in a statement.
Ernst has emerged as the front-runner in Iowa's crowded GOP Senate primary. The winner of that election will face Rep. Bruce Braley (D-Iowa) in the fall.
Democrats pounced on the comments.
"Iowans should be gravely concerned that Joni Ernst continues to perpetuate a myth that both President Bush and Vice President Cheney have said was untrue. This is a debate that was settled many years ago, and all Iowans and Americans want U.S. Senators who can use the lessons of the past to build a smarter foreign policy moving forward. Ernst’s denial of the facts is immensely troubling," Iowa Democratic Party Chairman Scott Brennan said in a statement.
This post was last updated at 3:50 p.m.