The 2003 U.S. invasion of Iraq has come under fresh scrutiny this week, in the wake of questions posed to former Florida Gov. Jeb Bush about whether he would have supported the war if he knew then what is known now — that his brother, former President George W. Bush, acted on the mistaken assumption that Iraq had weapons of mass destruction.

It is a question that has been asked in one form or another of most of the major presidential contenders. Here is a roundup of what they have said recently.