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Former Rhode Island Gov. Lincoln Chafee announced he is running for president on Wednesday, becoming the third Democrat to challenge Hillary Clinton.

“Today I am formally entering the race for the Democratic nomination for president,” Chafee said in a university auditorium just outside Washington, D.C.

His announcement speech focused on finding “a way to wage peace.” The former Republican highlighted his opposition to the Iraq war, called for an end to drone strikes, and said he would reinvigorate the United Nations and further engage Russia.

He also said Edward Snowden should be allowed to come home and the U.S. should rethink the war on drugs. And, in one of the more unique policy positions outlined in a campaign speech this year, Chafee proposed the U.S. switch to the metric system.

“Here’s a bold embrace of internationalism: let’s join the rest of the world and go metric,” he said. During a question and answer session the former senator said it would be “symbolic integration” and a good-faith gesture to the rest of the world.

The longshot candidate also knocked frontrunner Hillary Clinton for recent controversies surrounding her private email server as donations to the Clinton Foundation while she was secretary of state.

“Our State Department just has to be above all controversy, and it’s regrettable to me what’s happening now with emails, with the foundation that affects decision making coming out of State. We just can’t have that,” said Chafee.