In the next few days, a majority of senators are likely to vote to get the federal government, for the first time, in the business of killing human embryos for research purposes. President Bush has vowed to veto the bill, and he has the votes in the House to sustain his veto. So the only effect of a “yes” vote will be for senators to put themselves on record in favor of this noxious idea.

In 2001, Bush announced that the government would fund research on existing stem-cell lines. He did not, however, want federal funds to encourage anyone to kill human embryos to derive more stem-cell lines. He thus refused to fund research on stem-cell lines derived after the funding was announced. Senators are being asked to vote to lift this restriction. The bill would permit funding on stem-cell lines derived from “leftover” human embryos at fertility clinics.

Even if the bill were to become law — which it will not as long as this president is in office — it would not accomplish much. Science might progress a little faster. But it is pretty clear that research using cloned human embryos and fetuses has more to offer than research using the embryos at fertility clinics. That type of research cloning is still unpopular. The political point of the current bill is thus to pave the way for it.

There are also other, ethical scientific alternatives that hold more promise. A second bill would fund research that seeks to develop ways of producing the equivalent of embryonic stem cells without killing human embryos. Such research would be in addition to ongoing, federally funded research on stem cells taken from adults’ tissues and from umbilical-cord blood. It would also come on top of private-sector research that is proceeding in all of these directions. A third bill would impose the first limits on such research by outlawing fetal farming.

Some politicians who object to subsidizing the killing of embryos are worried about the political consequences of voting against the bill. They shouldn’t be. It is true that most polls show public support for embryonic-stem-cell research. But that support drops substantially when it is clear that the research would be taxpayer-funded and would kill human embryos. In 2005, CBS found that the public approved “of medical research using embryonic stem cells” by a 58-31 percent margin. But when CBS asked whether the federal government should limit funding to existing stem-cell lines or increase the number, enough of the supporters defected to the conservative side to produce a 48-37 percent plurality for the president’s policy.

The poll results depend greatly on the wording of the question, which suggests that the public does not have firm views on this matter. Democrats tried to make an election issue out of stem cells in 2004, without obvious success. Nobody has ever lost a race by opposing embryo-killing stem-cell research (or, unfortunately, by supporting it). Senators should feel free to vote on the merits. Those merits counsel a vote for imposing some ethical limits on stem-cell research, for funding ethical research, and against funding the embryo-killing kind.