The political career of former Rhode Island senator and governor Lincoln Chafee tells a story of the Republican Party: How it swerved so far right that to remain sane he finally had to switch sides, in a transition completed Wednesday evening at George Mason University, where he announced his run for the Democratic nomination for president with the rallying themes of “waging peace” and “future ideas.”

Once a “liberal Republican” (two words that simply do not appear together anymore), Chafee has taken stances not only to the left of many in his former party, but even occasionally to the left of the leading Democratic candidate, Hillary Clinton. He even says he wants to bring Edward Snowden home.

Here are five things you should know about this idiosyncratic candidate.

1. He voted against the Iraq War.

Chafee was the only Republican in the Senate to vote against authorization for the Iraq War in 2002. He has not hesitated to bring attention to the fact that Clinton failed to do the same when she was a senator from New York. “I don’t think anybody should be president of the United States that made that mistake,” Chafee told the Washington Post.

“They knew there were no weapons of mass destruction, but they wanted their war badly enough that they were willing to deceive us,” Chafee said in his announcement speech Wednesday night. “There was no intelligence. Believe me. I saw everything they had.”

2. He has supported marriage equality for a while.

Rhode Island became the eighth state to legalize same-sex marriage after Chafee signed a marriage equality bill into law in 2013.

He published an op-ed in the New York Times at the time, defending his decision as both a deeply moral and eminently practical one, enjoining other state governors to recognize that marriage equality would be a boost for their state’s economy. In the same op-ed, he expressed his desire for the Supreme Court to strike down the Defense of Marriage Act, which it did one month later. 

3. He’s cautiously supportive of the Trans-Pacific Partnership.

Splitting ranks with heavy-hitting progressives, such as Senators Elizabeth Warren (D-MA) and Bernie Sanders (I-VT), Chafee said he was supportive of the Trans-Pacific Partnership, asserting Wednesday night that the trade deal “has the potential to set fair guidelines for the robust commerce taking place in the Pacific Rim,” according to his prepared remarks.

4. He isn’t what conservatives would call “tough on crime.”

In his speech he spoke of the need to “wage peace” in our own hemisphere, by rethinking the country’s destructive, ineffective War on Drugs. “Obviously, eradication, substitution and interdiction aren’t working. Let’s have an active, open-minded approach to drug trafficking,” he said.

On domestic policing, he was unequivocal, saying in response to a student’s question: “Zero tolerance doesn’t work,” citing “police brutality” and the lack of available education.

5. He wants America to use the metric system.

Near the end of his announcement speech, at the bottom of a long list of “many and formidable” challenges, Chafee said he wanted to move the U.S. toward the metric system, also called the International System, since basically everyone except us uses it.

Far from a frivolous move, Chafee said it was part of a “bold embrace of internationalism.” After all, the U.S. is one of only three countries that doesn’t use metric; the other two are Liberia and Burma.

“It’s not that hard” to use Celsius, he said.

Photo: Governor Lincoln Chafee (RI), September 19, 2011, via Facebook