Senate Challenge to Bush on Stem Cell Research

In a rare challenge to the authority of President George Bush by a senior Republican, the Senate majority leader, Bill Frist, yesterday said he would support legislation to remove some of the administration's limitations on embryonic stem cell research.

The move is likely to result in a showdown between Mr Bush and the Senate, as the president has promised to veto legislation for expanded financial support for stem cell research on moral and ethical grounds.

Mr Frist - a heart and lung transplant surgeon, and a close ally of the president who has been courting religious conservatives for a possible future presidential bid of his own - had previously said he supported the White House policy of limiting stem cell research.

But in a lengthy speech on the Senate floor yesterday morning, Mr Frist said that while he still had reservations, he now supported a bill passed in the House of Representatives last month to expand funding. "While human embryonic stem cell research is still at a very early stage, the limitations put in place in 2001 will, over time, slow our ability to [create] potential new treatments for certain diseases," he said.

"Therefore I believe the president's policy should be modified."

The bill deals with embryonic stem cells, which are the building blocks for every tissue in the body. Attempting to harness those cells' regenerative powers is in early research stages, but many scientists believe it has the potential to create breakthrough treatments for diseases including Parkinson's and Alzheimer's.

Mr Bush claims the research destroys life because embryos are destroyed in the process. But supporters point out that there are embryos in fertility clinics that would be discarded and never used to create babies, but could be used for research purposes.

Almost two-thirds of Americans say they support embryonic stem cell research and a majority of people say they would like to see fewer restrictions on taxpayer funding for research.

But Christian conservatives, whose support is seen as crucial for any Republican hoping to get the party's presidential nomination, are vehemently against stem cell research, which they liken to abortion.

"I am pro-life," Mr Frist said in the speech, arguing that he could reconcile his support for the science with his own Christian faith. "I believe human life begins at conception."

Mr Frist's change of heart does not fatally flaw any presidential aspirations he might have, as it could help him win support among centrists.

The stem cell research bill has been stalled in the Senate, but commentators predicted yesterday that other Republicans who had been wary of supporting it may now feel they have licence to do so.

A vote on the bill is unlikely before September, but if the Senate does pass the legislation it could result in Mr Bush using his veto power for the first time.

Supporters of stem cell research were elated by Mr Frist's support for the bill. "This is critically important," Larry Soler, a lobbyist for the Juvenile Diabetes Research Foundation, told the New York Times. "[He] is confirming the potential of embryonic stem cell research and the need to expand the policy."

The Republican senator Arlen Specter, who is fighting cancer, called Mr Frist's decision "perhaps the most important speech made on the floor this year, and perhaps the most important speech made in many years".

The Democratic senator Edward Kennedy said: "As a physician, Senator Frist has a moral calling to alleviate suffering. He honours his Hippocratic oath today by recognising the unique healing power of embryonic stem cells."