Washington ? The Senate voted Tuesday after two days of emotional debate to expand federal funding of embryonic stem cell research, sending the measure to President Bush for a promised veto that would be the first of his presidency.

The bill passed 63-37, four votes short of the two-thirds majority that would be needed to override Bush’s veto. The president left little doubt he would reject the bill despite late appeals on its behalf from fellow Republicans Nancy Reagan and Arnold Schwarzenegger.

“The simple answer is he thinks murder’s wrong,” said White House spokesman Tony Snow. “The president is not going to get on the slippery slope of taking something living and making it dead for the purposes of scientific research.”

Polls show as much as 70 percent public support for embryonic stem cell research.

Democrats are portraying Bush and his allies as captives of a dogmatic segment of the GOP that is blocking possible cures for major diseases.

“This is the kind of issue that voters use to distinguish members who are beholden to the far right,” said Rep. Chris Van Hollen, D-Md., a chief recruiter of Democratic House candidates for this fall’s elections. “Every family in America is touched by someone who could benefit” from embryonic stem cell research.

Sen. Sam Brownback, R-Kan., right, joins Cathy Pell and her daughter, Abby, during a Capitol Hill news conference to discuss stem cell research. The conference was Monday, a day before the Senate voted to approve funding for embryonic stem cell research. Brownback is a proponent of using adult stem cells; both he and Kansas Sen. Pat Roberts voted against the embyronic stem cell bill.

In a surprise victory for embryonic stem cell supporters, the House defeated a second bill that would have encouraged stem cell research from sources other than embryos. Opponents of that bill, sponsored by Sen. Rick Santorum, R-Pa., called it election-year cover that would allow Bush and other embryonic stem cell opponents to say they nonetheless support stem cell research.

While the Senate approved that measure unanimously, the House’s 273-154 vote fell 12 votes short of the two-thirds majority required for passage under the rules. The House could try again to pass the bill today by a simple majority and send it to Bush for his signature.

Meanwhile, both the House and Senate unanimously approved a related bill, which Bush was expected to sign into law, to ban so-called “fetal farming,” the prospect of raising and aborting fetuses for scientific research.

Embryonic stem cells are essentially master cells, able to morph into all the cell types found in the body. If scientists could learn to control these cells and coax them into becoming specific types on demand, they could grow replacements for damaged tissue. The idea is to use this process – still theoretical – to cure or treat a raft of diseases and injuries, from diabetes to Alzheimer’s and spinal cord damage.