Washington CNN  — 

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.

RELATED: Clinton too ‘Bush-like’ on foreign policy, Chafee says

Chafee’s strategy on the Iraq War is simple: Damage Clinton on an issue on which he was diametrically opposed. Chafee has said he doesn’t worry about staking his campaign on a backward looking issue, and is proving that by repeatedly returning to the Iraq War vote in interviews.

So far, however, the issue has failed to move the needle for Chafee. In a May CNN/ORC poll, the former governor failed to get even 1% support from self-identified Democrats and independents. In the same April poll, the former senator received 1%.

He is more liberal than Clinton on other issues, too. He supported gay marriage before she did, for instance. But he is more of a hawk on fiscal matters.

Chafee, a former horseshoe specialist, told CNN in April that he wouldn’t bet on himself in the 2016 race, but added that he isn’t concerned with his abysmal polling.

The election is a “long, long way away. And any political historian can give innumerable examples of 1 percenters who have gone on to success,” he said. “Maybe even Bill Clinton himself?”

From the start, Chafee has been a somewhat reluctant candidate. He announced he was exploring a run with such an understated video and website that nearly every political journalist and operative were blindsided by the decision.

And, according to his spokesman, Chafee backed into his decision to announce on Wednesday. After getting ahead of himself by telling reporters, including CNN, that he was “running,” Chafee and his team knew they had to announce soon.

Chafee will head straight to New Hampshire, a state he and his advisers say he has to do well in to have any chance at winning the presidency.

After visiting Keene, New Hampshire for a meet and greet with local Democrats on Tuesday night, Chafee will hold a similar event in Lebanon, New Hampshire.

“I am new at this. But I am a New Englander, so New Hampshire voters have heard of me, read about me in the Boston Globe,” Chafee said in an interview last month. “I haven’t campaigned in either state, so I don’t know what to answer.”