House Republican leaders announced plans Monday for congressional investigations into a wide range of issues, from corruption in Afghanistan to Washington's regulation of private industries, using the power of their new majority to launch probes that could embarrass the Obama administration.

Rep. Darrell Issa (R-Calif.), who will become chairman of the House Oversight and Government Reform Committee when the 112th Congress is sworn in Wednesday, said he would lead six major investigations in the first three months of the year. This is an ambitious undertaking by conventional standards, as congressional investigations often take months to bear fruit.

Issa, who will have power to subpoena government officials to appear before the committee, said he intended to conduct inquiries into the release of classified diplomatic cables by Wikileaks; recalls at the Food and Drug Administration; the role of Fannie Mae and Freddie Mac in the foreclosure crisis; the Financial Crisis Inquiry Commission's failure to identify the origins of the meltdown; as well as business regulations and alleged corruption in Afghanistan.

Other incoming Republican committee chairmen are planning investigations into the Justice Department's civil rights division, the radicalization of Muslims in the United States, homeland security grant money and air cargo and port and chemical plant security.

Every turnover in Congress fuels anticipation about how the new majority will scrutinize the administration. In Issa's case, the combative Republican has tempered his partisan rhetoric recently and appeared to steer clear of undertaking investigations that could be seen as overtly political. But his ambitious agenda sets up a potential early showdown between the White House and emboldened House Republicans.

Issa outlined plans to ask administration officials to testify, including national security adviser Tom Donilon, whom he wants to question about whether the administration has a strategy to stop the dissemination of sensitive information by sites like Wikileaks.

"I've always been fond of the saying that when it comes to oversight and reform, the federal government does two things well: nothing and overreact," Issa said Monday. "Too often, a problem is allowed to fester until it reaches a crisis point. . ..and the American people are left asking the question: what went wrong and why?"

Rep. Peter T. King (R-N.Y.), the incoming chairman of the Homeland Security Committee, said he plans to investigate the apparent radicalization of some Muslims in the United States and the extent to which American Muslims are cooperating with law enforcement authorities. He also plans to probe homeland security issues.

"Different from Darrell Issa, I'm not expecting to find significant corruption in the departments," King said in an interview. "To the extent there's disagreement, it will be philosophical disagreement and a question of leadership, whether or not the department is assertive enough."

Rep. Lamar Smith (R-Tex.), who is taking over the House Judiciary Committee, is planning investigations of the Justice Department, including allegations that the civil rights division is not fairly enforcing voter rights laws, according to a senior aide.

Since Democrats control the Senate, the White House and federal agencies, Republicans can use House oversight hearings to slow down policies and practices they disapprove of.

"The ability to hold hearings is a tool to help shape public opinion, put pressure on the Senate and maybe allow you at the end of the day to get concessions from the administration," said former Republican congressman Vin Weber, a Washington lobbyist.