If you've been paying attention to the news in the past few months, you know the top two candidates in Tuesday's Democratic debate pretty well by now.

There will be three lesser known candidates next to Sen. Bernie Sander (I-Vt.) and former secretary of State Hillary Clinton. Of those, which one thinks the metric system is just what the United State needs?

Former Rhode Island governor Lincoln Chafee (D).

Watch this video to see what you need to know about Chafee in 30 seconds or less.

Chafee first came to Washington as a Republican senator from Rhode Island, appointed to take the seat of his father, John Chafee, when he died. He officially left the Republican party in 2007 after losing a bid for reelection to the Senate. As an independent, he was elected governor of Rhode Island in 2010. Three years later, he joined the Democratic party.

Post Politics called Chafee's presidential bid a long shot when he jumped into the race in June. Recent polling shows that assessment still holds.

In the past 90 days, Americans have searched for Chafee on the Internet a little more than half as much as they have former Virginia senator Jim Webb. That said, search interest in Sanders and Clinton respectively still dwarfs interest in Webb and Chafee.

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