Conservative columnist Charles Krauthammer argued Friday that House Republicans should stop trying to catch the Obama administration in an ethical scandal because they've failed in each attempt so far, and instead have attracted criticism for their efforts.

His advice comes after Hillary Clinton testified in front of the GOP-led House Select Committee on Benghazi, after which many agreed Clinton emerged unscathed. House GOP leadership recently said they would try to impeach the head of the IRS, in light of a decision by the Justice Department that it would stop investigating the agency for alleged unfair targeting of conservative groups.

"At a certain point, you have to realize you can't hit a fastball. House Republicans don't quite get that they are hopeless at oversight hearings. They keep losing," Krauthammer wrote.

"I'm all for demonstrating malfeasance," he added. "But the GOP House has given a five-year display of its inability to successfully demonstrate anything. From Benghazi all the way back to [the gun-traffic sting] Operation Fast and Furious, its hearings' impact on public perception has been either zero or negative."

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