In it, but not of it. TPM DC
In line to helm this committee would be Sen. Chuck Grassley (R-IA), the panel's ranking member since 2011. As chairman of one of the most powerful committees in the Senate, he'd be tasked with oversight of the Obama administration -- including its actions on crime, terrorism, immigration, and administrative actions -- and putting judges on the courts. He'd be the counterpart to House Oversight Chair Darrell Issa (R-CA) in searching for White House scandals and seeking to embarrass the president.
The next chairman would probably be Sen. Orrin Hatch (R-UT), the ranking member since 2011. The influential panel -- which has jurisdiction over taxes, entitlements and health spending -- is a chief mover and shaker in the Obamacare debate. Hatch has been a thorn in the White House's side, and as chairman his investigative powers would be greatly expanded.
Environment & Public Works Committee
Leading the committee would likely be Sen. James Inhofe (R-OK), who was chairman for four years before Republicans lost their majority in 2007. He'll have two more years in the role under the Senate GOP's self-imposed six-year term limit. Inhofe has taken a keen interest in the committee's subject matter, becoming the Senate's most outspoken denier of the scientific consensus that climate change is real and man-made.
Armed Services Committee
Sen. John McCain (R-AZ) would have seniority to chair the panel, which oversees the military and national security issues. McCain, a leading Republican voice on security and terrorism, is a frequently critic of his 2008 rival on national security matters, and his hypothetical perch at Armed Services would make him an obstacle for Obama.
Sen. Jeff Sessions (R-AL) is currently the top Republican and presumably next in line to be chairman. He's a fervent supporter of Rep. Paul Ryan's (R-WI) efforts to remake the federal budget and a strong critic of welfare programs. But sources say Sen. Mike Enzi (R-WY), a senior budget member, may also run for the chairmanship.
Health, Education, Labor and Pensions Committee
This committee would likely be led by Sen. Lamar Alexander (R-TN), the current ranking member, and a close ally of McConnell. The panel has jurisdiction over a variety of domestic issues affecting middle income and poor people, including Obamacare to an extent.
Next in line to chair other committees: Sen. Bob Corker (R-TN) at the Foreign Relations Committee, Sen. Richard Shelby (R-AL) at the Appropriations Committee, Sen. Mike Crapo (R-ID) at Banking Committee and Sen. Mike Enzi (R-WY) at the Homeland Security Committee (if he doesn't lead the Budget Committee).