Koch Industries' PAC and affiliated individuals have given Ryan a total of $65,500. Koch brothers have Paul Ryan's back

Critics of the Koch brothers should have a field day with Rep. Paul Ryan on the GOP ticket: They've been one of his biggest campaign contributors.

Koch Industries ranks as the Wisconsin Republican's sixth-largest source of campaign money throughout his career, according to the Center for Responsive Politics, which says the company's PAC and affiliated individuals have given him a total of $65,500 in donations.


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That also ranks Koch as Ryan's biggest energy-related donor, based on the center's tally. It says energy- and natural resources-related contributors have given Ryan a total of $432,181 during his career, including $244,250 from the oil and gas industries.

( PHOTOS: Paul Ryan's career)

The Kochs, a perpetual lightning rod for criticism from the left, have been especially active during this election in funding groups attacking President Barack Obama and his energy policies. One Koch-supported group, Americans for Prosperity, has put a special focus on ads highlighting the failure of the solar company Solyndra — also a major theme of Romney's campaign.

This article first appeared on POLITICO Pro at 6:18 a.m. on August 11, 2012.