MADISON, Wis. (AP) — Wisconsin Governor Scott Walker has announced on social media that he's running for president, tweeting "I'm in."

Walker, a Republican who built a national profile largely due to his clashes with labor unions, also released a campaign video at the same time Monday declaring his entry in the race.

The video is heavy on images of Walker speaking to a crowd in an Iowa cornfield, as well as his 2010 battle with unions.

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