When Republican leaders in 2010 tapped Rep. Darrell Issa to lead the House Oversight and Government Reform Committee, a top congressional watchdog panel, Democrats responded with an unusual move.

House Minority Leader Nancy Pelosi passed over Rep. Edolphus Towns, the committee's most senior Democrat, and tapped Rep. Elijah Cummings to be the panel's ranking Democrat opposite Issa.

Pelosi never offered much of a explanation for casting aside Towns, who subsequently retired. But Republicans claim Cummings was given the seat because Democrats thought he would be more aggressive in countering Issa, whom they feared would launch partisan investigations into the Obama administration.

Cummings hasn't disappointed. The Maryland Democrat has been particularly effective in creating public doubt about Republican charges that the Internal Revenue Service practice of targeting conservative groups seeking tax-exempt status was initiated in Washington, from inside the Obama administration if not the White House.

Against Issa's wishes, Cummings recently released a transcript of testimony of an IRS manager from Cincinnati who described himself as a Republican and told congressional investigators that the targeting began in the Cincinnati office, not Washington as Republicans suspect. The manager also claimed that the targeting was not politically motivated, as GOP lawmakers charged.

Cummings also demanded that Issa get additional testimony from Treasury Inspector General J. Russell George, who uncovered the IRS targeting. Cummings claims George withheld information during his first appearance before the committee, including emails that Cummings said prove IRS employees acted out of confusion, not political malice.

Cummings, who represents Baltimore's inner city, told the Washington Examiner that his goal in not to block Issa but to pursue the truth.

"In my neck of the woods, it means a lot," Cummings said. "I'm the son of two Pentecostal ministers."

Cummings believes the IRS targeting stemmed from poor management exacerbated by a flood of tax-exemption applications from groups that wanted to get involved politically after a Supreme Court decision cleared the way for them to do so. "Did they do everything right? No," Cummings said of the IRS employees in the Cincinnati office, whom he still believes were primarily responsible. "Should they have done the targeting? No. But I think their intention was trying to do the right thing."

The IRS needs to be reformed, he said, but without the partisan sniping.

"I don't think that the American people want us to destroy the IRS," Cummings said. "I think they want us to make sure it works the way it is supposed to work."