Supporters of the bill, sponsored by Sens. Tom Harkin (D-Iowa) and Arlen Specter (R-Pa.), however, remain one vote shy of the 67-vote, veto-proof threshold they sought.

The Senate passed the bill 63 to 34. Although the vote was four short of the supermajority needed to override a veto, three senators who support the bill missed the vote.

Last year, President Bush issued his first-ever veto on legislation containing the same language that the House and Senate have passed again this year. A House vote to override that earlier veto failed.

The bill would end a policy Bush established in 2001 that strictly limits federal funding for research to drive stem cells from human embryos. Many scientists believe these cells are potentially useful in treating diseases such as diabetes and Alzheimer’s. Opponents object because the research destroys human embryos.

In addition to Specter, 16 Republicans voted for the bill, including Sens. Orrin Hatch (Utah), John McCain (Ariz.) Gordon Smith (Ore.) and Minority Whip Trent Lott (Miss.). Democratic Sens. Ben Nelson (Neb.) and Bob Casey Jr. (Pa.) voted against the bill. Three Democrats did not vote: Sens. Chris Dodd (Conn.), Tim Johnson (S.D.) and Mary Landrieu (La.).

Democratic victories in Senate contests last year in Missouri, Montana, Ohio and Virginia led to four more votes in favor of the measure than it received last year. Those gains, however, were partially offset by the nay vote of Sen. Bob Corker (R-Tenn.), who replaced former Majority Leader Bill Frist, a supporter of the measure.

Vote counters had been keeping a close eye on Sen. John Sununu (R-N.H.), who voted against the bill last year but is up for reelection next year. Sununu held his ground in opposition to the measure.

The House passed a similar bill, sponsored by Reps. Diana DeGette (D-Colo.) and Mike Castle (R-Del.), in January by a vote of 253 to 174, which is well short of the two-thirds needed to overturn a veto.

The Senate Democratic leadership is expected to bring the measure back to the floor to reconsider the veto.

The absence of Johnson, who is recuperating from a brain ailment, complicates efforts to overturn the veto but if the Senate manages to attain a supermajority, a House vote on the veto would follow.

In the meantime, the House will either bring the Senate-passed version directly to the floor or merge the two bills in conference committee, which would require both chambers to pass a conference report.

The bill’s supporters also plan to revisit the issue via other legislative vehicles throughout the 110th Congress.

The Senate also approved another stem cell bill, sponsored by GOP Sens. Norm Coleman (Minn.) and Johnny Isakson (Ga.), that would direct federal funding to research on alternative means of deriving stem cells that does not require the destruction of human embryos, including using embryos that are certified as already dead.

The Coleman-Isakson bill passed 70 to 28 but the House leadership has not committed to taking up the measure.