Plenty of actors get reputations for being difficult to work with. If the Directors Guild of America's May PAC donations are any indication, cameo actor Patrick Leahy—who also happens to be the longest-serving Democrat in the Senate—has a better relationship with his on-set bosses.

The Vermont senator, who has appeared in multiple Batman movies in bit parts (in 2008's The Dark Knight, Heath Ledger's "Joker" holds a knife to his character's mouth), received $10,000 worth of donations from the Guild's PAC last month. The money, split evenly between Leahy's reelection campaign and his leadership PAC, is the most that the Guild, a union representing film and TV directors, has given to any candidate so far this year.

Leahy is set to appear on the silver screen again in Batman v Superman: Dawn of Justice. But his part-time acting career is likely not what has drawn the Directors Guild's attention. Leahy's position as ranking member on the Senate Judiciary Committee means he is a powerful advocate for intellectual-property rights, a policy priority for filmmakers hoping to prevent pirating.

"For decades, Senator Leahy has been a leading voice both in protecting this nation's intellectual property and in safeguarding the rights of content creators against threats to their livelihoods and creative freedom," said Guild spokeswoman Lily Bedrossian.

The Guild honored Leahy in 2011, for fighting "digital theft and counterfeiting."

The group's PAC has given $25,000 to Leahy or his leadership PAC in previous elections and another $4,500 to the Vermont Democratic Party before his 2004 reelection, according to the Center for Responsive Politics.

Leahy is far from the only member of Congress to benefit from the PAC's largesse—New York Sens. Kirsten Gillibrand and Chuck Schumer, former House Majority Leaders Eric Cantor and Richard Gephardt, Republican Reps. Bob Goodlatte and Marsha Blackburn, and Democratic Reps. Charles Rangel and John Conyers all have gotten major campaign donations from the Directors before. Local Rep. Adam Schiff is one of several other members of Congress to receive a donation this year.

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