'Bush must be acting out of conviction [in threatening a veto] because the politics just don't add up,' said Thomas Mann, a Brookings Institution scholar. The vote 'reflects the broad support for stem cell research, even among those who consider themselves pro-life.'

One of 50 Republicans who voted for a House bill last week that would expand federally funded stem cell research using discarded embryos, Cunningham said Bush should drop his threat to veto the measure. Embryonic stem cell research potentially "is the future of medicine," he said, holding promise to cure many diseases.

Stronger GOP support for expanded embryonic stem cell research reflects a political shift on the issue that puts Bush and the White House in a defensive position. Polls indicate 60 percent of Americans favor such research, and Republicans are sharply split on the question.

'A Matter of Time'

A Pew Research Center poll in 2002 indicated that Americans, by a 43-38 margin, favored performing research on stem cells over protecting embryos. In a poll at the end of 2004, that margin was 56-32.

Rep. Mark Kirk (R-Ill.), a moderate who supported the bill, said it's only a matter of time before there is a veto-proof majority in Congress for expanded embryonic stem cell research.

While Bush firmly rejects the bill on the grounds it would allow the use of federal dollars for the destruction of embryos, using the issue to fire up the Republican base in 2006 congressional elections may have limited impact. The GOP base includes many social conservatives opposed to stem cell research, but the vote last week showed a growing number of GOP congressional supporters.

"Bush must be acting out of conviction [in threatening a veto] because the politics just don't add up," said Thomas Mann, a Brookings Institution scholar. The vote "reflects the broad support for stem cell research, even among those who consider themselves pro-life."

'A Better Road'

Opponents call expanded financed stem cell research unethical and immoral, and that is essentially Bush's position. Considering that support for the bill is strong in the Senate, Bush would be faced with vetoing a bill that has strong congressional and public backing.

"The problem is that opposing the bill that passed the House is akin to opposing abortion in the case of rape," said Republican political consultant Whit Ayres. At the very least, the House vote suggests the embryonic stem cell research issue may have limited utility for Republican candidates in future elections, unless public opinion turns around on the issue.

GOP members who bucked the president not only were emboldened by public opinion polls but also by adverse public reaction to Congress' intervention in the Terri Schiavo case, Mann said. With Bush's support, Congress approved legislation aimed at restoring Schiavo's feeding tube. But state and federal courts rebuffed this effort, and Schiavo died.

Cunningham said when he speaks to anti-abortion groups about his position on stem cell research, 90 percent to 95 percent of the people understand. The congressman said he changed his position on the issue two years ago when a prominent San Diego medical scientist, Lawrence Goldstein, convinced him that many of the embryos in question would otherwise be discarded. He said he would convey that message to Bush.

"I am going to give him the best logic that I have," Cunningham said. "I know he's a man who does what he says. I found that if you can show him where there could be possible movement, he's not stubborn and he will do that. He's pretty clear-thinking. It's not just 'a my-way-or-the-highway kind of thing.' You can show him there's a better road."

An Ethical Way to Conduct Research

There are limits to this shift in attitude about the highly controversial issue. Cunningham, for example, restricts his support to allowing federally funded stem cell research on frozen embryos that are now in in-vitro fertilization clinics and that would be discarded. He said he opposes using cloned embryos in such research and the "harvesting" of embryos for stem cell research purposes.

"The politics of this is something like the politics of abortion, in that most people reject the positions at the end of the [political] spectrum," said Ayres. "Most people are dead set against cloning and creating embryos for the purposes of research.

"On the other hand, most people would like to find an ethical way to conduct research that has enormous promise for addressing debilitating diseases," Ayres said.

Kirk, who played a key role in the House leadership's decision to stage the vote, believes that prominent conservative Republicans such as Sen. Orrin Hatch of Utah could persuade Bush to change his mind. As a co-sponsor of the Senate measure to expand research on discarded embryos, Hatch said last week that the legislation is "pro-life," because the stem cells would be used to prolong life, cure disease and ease suffering.

Politics of Stem Cell Research

Some Republicans who consider themselves anti-abortion voted for the House measure last week, including Cunningham; Joe Barton of Texas, who is chairman of the Energy and Commerce Committee, and William Thomas of California, who is chairman of the Ways and Means Committee.

Charles Jones, a retired political science professor at the University of Wisconsin and a Brookings Institution scholar, said there's little question that the politics of stem cell research has shifted, partly because more lawmakers have become convinced that the research could lead to some dramatic medical breakthroughs.

"It's almost one of those issues that rises above what we have seen in the normal partisan divide," he said, adding that he saw no particular political advantage for Bush if he vetoed the bill. While a veto might please the GOP political base, he said Bush is a lame-duck and wouldn't be helped. Nor would a veto help Republicans who had voted for the bill, Jones said.

Lawmaker Disappointed

Rep. Bart Stupak (D-Mich.), a strong opponent of the bill, said he was disappointed with distortions in the debate.

"You had these great statements on both sides about how this is the next great breakthrough in medical science," he said. "Everything I have seen suggests that it is decades away. I hope that by our actions, it will not give false hopes to people."

Stupak also said alternative sources of stem cells -- adult stem cells taken from bone marrow and umbilical cord blood -- hold more promise for immediate breakthroughs.

Cunningham said Goldstein, director of cellular and molecular medicine at the University of California, San Diego, convinced him that many of the embryos would be thrown away.

"If they are going to be thrown away and not become life, that's the reality of it," he said. "The group that voted against this will just not see reality."

Robert Moffit, a health-care expert at the Heritage Foundation, a conservative think tank, said the private sector currently could conduct embryonic stem cell research. If the science has such big-figure payoffs, he said, "Why do they [private companies] need federal funds for it?"