Updated

Dr. John Barrasso began his rounds on Capitol Hill on Monday, learning how to be a senator.

Barrasso, a conservative Republican surgeon who was until now a Wyoming state senator, was sworn in by Vice President Dick Cheney Monday afternoon. Gov. Dave Freudenthal selected him to fill the seat of Sen. Craig Thomas, who died June 4 while being treated for leukemia.

At a photo session with Senate Minority Leader Mitch McConnell, R-Ky., and Wyoming's other senator, Republican Mike Enzi, Barrasso said that his predecessor was a great man and that he, like Thomas, planned to be home in Wyoming often.

He declined to answer any questions, walking out of the room with his new colleagues as a reporter asked how he would vote on an immigration measure.

Barrasso's week starts with easier tasks, such as getting his credentials and learning how to set up his office. But all eyes will be on the rookie senator as a host of controversial issues are debated in the coming days, including immigration and federal funding for the use of embryonic stem cells.

The Democrats hold a slim 51-49 majority in the Senate, and one Democrat, South Dakota Sen. Tim Johnson, is absent from the chamber recovering from a December brain hemorrhage.

Senate Majority Leader Harry Reid of Nevada put off a vote on overriding President Bush's latest stem cell research veto until after Thomas' replacement was selected.

Barrasso has so far declined to say how he will vote on the issue, but he is not expected to stray far from his party's policies. During the selection process for a Thomas replacement, Barrasso said he believes in limited government, lower taxes, traditional family values and a strong national defense. He emphasized that in the state senate, he sponsored legislation "to protect the sanctity of life."

Barrasso will serve until the beginning of 2009. A special election in November 2008 will decide who will finish Thomas' term, which runs to January 2013.

McConnell said Barrasso has big shoes to fill but "by all accounts, he's up to the job."

"Given the age of this institution, it's good to have another physician," McConnell said.

Sen. Tom Coburn, an Oklahoma Republican, also is a doctor.

Barrasso was accompanied by several members of Thomas' staff, who will now work for him. At his swearing in, Enzi and former Wyoming Sen. Malcolm Wallop, also a Republican, stood by his side.

Wyoming law is designed to keep the same party in power in the event of a Senate vacancy. Democratic Gov. Freudenthal chose Barrasso from a pool of three Republicans nominated by the state GOP.