Sen. Craig Thomas, R-Wyo., died Monday at the National Naval Medical Center in Bethesda, Md., where he was undergoing treatment for leukemia.

His family announced the death in a statement, according to the Associated Press.

Thomas, 74, was diagnosed with leukemia in November, a day after easily winning re-election to a third term.

According to his office, he had been treated with a second round of chemotherapy, but his blood cancer was “resistant to their most recent efforts.”

Wyoming Gov. Dave Freudenthal, a Democrat, will name a replacement, who would serve until a successor can be chosen in a November 2008 special election. But under Wyoming law, he must choose from a list of three candidates put forward by the Republican State Central Committee because Thomas was a Republican.

Thomas was a member of the Finance Committee as well as the Energy and Natural Resources, Environment and Public Works, and Indian Affairs panels.

Like most Western lawmakers, he was a fiscal conservative who strongly supported oil and gas exploration on public lands, protecting private-property rights and farmers’ issues.

The senator’s wife, Susan, was at his side at the hospital Monday, along with their sons, Patrick and Greg, and daughter, Lexie.

“Our thoughts and prayers are with Susan and the entire Thomas family,” said White House spokesman Scott Stanzel. “Sen. Thomas was a respected member of the United States Senate and a tireless advocate for the people of Wyoming. His service to our nation will be missed.”

In a statement, Senate Minority Leader Mitch McConnell, R-Ky., said, “Wyoming had no greater advocate, taxpayers had no greater watchdog, and rural America had no greater defender than Craig Thomas. The Senate is a lesser place without Craig here, but the State of Wyoming and our nation are much better places because he was here.”

First posted June 4, 2007 8:42 p.m.