LARRY BRINLEE/WTE The late U.S. Sen. Craig Thomas, R-Wyoming, speaks to members of the Wyoming House of Representatives during a visit to the Capitol on Feb. 23. Thomas spoke to both houses about some of the issues facing Congress in Washington, D.C.

The Associated Press

WASHINGTON (AP) - The death of Republican Sen. Craig Thomas will not change the balance of power in the Senate. Unlike many states, Wyoming law is designed to keep the same party in power after a vacancy.

Thomas, a conservative, died after a fight with leukemia that was diagnosed last year just as he was elected for a third term. He was 74.

The senator's family said he died Monday evening at National Naval Medical Center in Bethesda, Md. The family had said earlier in the day that his cancer had been resistant to a second round of chemotherapy for acute myeloid leukemia.

He had also developed an infection, his family said.

In accordance with state law, Gov. Dave Freudenthal, a Democrat, will appoint a successor from one of three finalists chosen by the state Republican party.

Freudenthal called Thomas' death "a very big loss to the people of this state," saying "he carried the values that we treasure in Wyoming to Washington and had many successes."

The governor officially notified the party of Thomas's death Tuesday, and the GOP now has 15 days to convene and choose the nominees. Once the governor receives the names from the party, he has five days to choose one.

The new senator will serve until the next general election in 2008, when a special election will determine who completes Thomas's term, which runs through 2012.

Democrats and Republicans each have 49 members of the 100-member Senate. But two independents vote and organize with Democrats, giving them the slim majority they presently hold. Sen. Tim Johnson, D-S.D., has been recovering from major illness and has not participated in Senate activities in months.

Thomas was hospitalized with pneumonia just before the 2006 election, but won with 70 percent of the vote, monitoring the election from his hospital bed.

Two days after the election, Thomas announced that he had just been diagnosed with leukemia.

President Bush called Thomas "a man of character and integrity known for his devotion to the values he shared with the people of Wyoming."

"He leaves a lasting legacy as a guardian of Wyoming's lands and resources and our country's National Parks," Bush said.

Vice President Dick Cheney, who held Wyoming's only House seat before Thomas replaced him in 1989, called Thomas a friend and said "he never let us down."

"Even in a time of serious illness Craig was faithful to his duties in the United States Senate," Cheney said. "His passing represents a profound loss to the Senate, to Wyoming, and to America."

Thomas was a low-key lawmaker who reliably represented the interests of his conservative state, often becoming involved in public lands issues. He worked in behind-the-scenes posts to oversee national parks.

Republican Mike Enzi, Wyoming's other senator, gave an emotional speech on the Senate floor Tuesday morning, his voice cracking as he spoke of his friend.

"Craig died as he lived, with his spurs on, fighting for Wyoming until the very end," Enzi said.

The state's only member of the House, Republican Barbara Cubin, said in a statement that Thomas was "a trusted colleague and a true friend."

Wyoming Democratic Party Chairman John Millin said Thomas brought "dignity and thoughtfulness" to the political process, and Wyoming GOP Chairman Fred Parady called Thomas a "true champion."

Senate leaders delayed votes Tuesday so that members could give tributes to Thomas on the floor. Majority Leader Harry Reid, D-Nev., praised the senator's tenacity and his work on lands issues.

"He told you how he felt," Reid said.

Senate Republican Leader Mitch McConnell called Thomas "a born fighter."

"We're consoled by the thought that he'll ride again," McConnell said.

Thomas entered Congress in a special election in 1989 to replace Cheney when he was named defense secretary by the first President Bush. Thomas won that race with 52 percent of the vote.

In 1994, Thomas won his first Senate race by beating former Gov. Mike Sullivan and was re-elected with 74 percent of the vote in 2000.

Thomas had previously served five years in the Wyoming Legislature.

He was born in Cody, Wyo., and was raised on a ranch. He graduated from the University of Wyoming with a degree in agriculture, then served four years in the U.S. Marines.

He is survived by his wife, Susan, and four children.