WASHINGTON - Dr. John Barrasso began his rounds on Capitol Hill today, meeting with Republican leaders and learning how to be a senator.

Barrasso, a conservative surgeon who was until now a state senator, was scheduled to be sworn in this afternoon. Wyoming Gov. Dave Freudenthal selected him to become the state's newest senator on Friday, filling the seat of Republican Craig Thomas. Thomas died while being treated for leukemia June 4.

At a photo opportunity with Republican Senate Leader Mitch McConnell of Kentucky and Wyoming's other senator, Republican Mike Enzi, Barrasso gave a quick comment for the cameras, saying that his predecessor was a great man and that he would, like Thomas, plan to be home in Wyoming often.

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

Barrasso's week will start out with easier tasks, like 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 months, 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 has put off a vote on overriding President Bush's latest stem cell research veto until after the vacancy is filled.

Barrasso has so far declined to say how he would vote on the issue, but he is not expected to stray far from his party's ideals. 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."

The new senator met on today morning with McConnell, who said he has big shoes to fill but "by all accounts, he's up to the job."

Barrasso was accompanied by several members of Thomas's staff, who will now work for him.

Shawn Whitman, chief of staff to both Thomas and Barrasso, said he was inspired by his old boss when he made the decision to head up Barrasso's office.

"He said, `You don't work to serve me, you work to serve the people of Wyoming,"' Whitman said. "That's the thought that keeps running through my head."