In a rare break with President Bush and anti-abortion conservatives, U.S. Senate Majority Leader Bill Frist on Friday endorsed legislation that would expand federally funded embryonic stem cell research.

Frist, a Tennessee Republican and surgeon who may seek his party’s presidential nomination in 2008, endorsed a bill already passed by the U.S. House of Representatives that would overturn the limits on the research Bush imposed in 2001.

His backing, which could alienate the most staunchly anti-abortion conservatives but attract support from moderates in a potential White House bid, significantly improves chances of the legislation passing.

Bush has vowed to veto the legislation because embryos are destroyed when the stem cells are extracted.

White House spokesman Scott McClellan said Bush had not wavered in his moral opposition to the research but when Frist informed him of his decision by telephone on Thursday night, the president told him, “You’ve got to vote your conscience.”

Patients suffering from diabetes, Parkinson’s disease, spinal cord injuries and other debilitating and life-threatening disorders have been clamoring for more federal dollars for stem cell research. Opinion polls show growing support for its expansion, even among many conservatives like Frist who generally oppose abortion.

“I am pro life, I believe human life begins at conception,” Frist said in a Senate speech. “I also believe that embryonic stem cell research should be encouraged and supported.”

House Majority Leader Tom DeLay and other House conservatives called on Bush to stick to his pledge to veto the bill. DeLay, a Texas Republican, likened “destructive embryonic stem cell research” to abortion and euthanasia.

The bill, approved in the House and likely to come up in the Senate after the August recess, would allow federally funded research on stem cells derived from leftover embryos in fertility clinics. There are currently about 400,000 such frozen embryos, many of which will otherwise be destroyed.

Frist said he wanted to see some relatively minor changes in the bill, but the legislation’s authors said his concerns would not complicate or delay passage.

By Joanne Kenen

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