Washington, D.C. – Lincoln Chafee formally announced his presidential bid on Wednesday. He has been elected to office as a Republican senator and an Independent governor. Now he’s got his sights set on the White House as a Democrat. “I enjoy challenges and certainly we have many facing America. Today, I am formally entering the race for the Democratic nomination for President,” he said.

A defining issue for Chafee has been the war in Iraq; he was the lone Republican to vote against authorizing the war as a senator in 2003. Hillary Clinton was among the Democrats to vote in favor of giving President George W. Bush the authority to invade. Chafee announced his bid in a speech at George Mason Center for Politics & Foreign Relations in Arlington, Virginia.

Chafee told CNN he feels Clinton’s vote should disqualify her from the presidency, even though it happened more than a dozen years ago. “Considering the premise for invading Iraq was based on falsehoods and considering the ramifications we live with now from that mistake, I would argue that anybody who voted for the Iraq War should not be president and certainly should not be leading the Democratic Party,” he said in an interview after he announced he was exploring a presidential run in April.

Clinton has said she regretted the Iraq vote, and told reporters last month that she “made a mistake, plain and simple.” The former governor made his decision to vote against authorizing the war a key argument behind his rationale for running.