While war dominates the headlines, a congressional debate is occurring that, within a decade, will be seen as a political turning point. In the stem-cell debate, Democrats are playing our culture card.

This column has regularly examined the rise of cultural politics — or more accurately the reemergence of culture as a defining cleavage in American politics. In fact, cultural divisions are a more natural and more common source of cleavage than economics. But I digress.

For years Democrats have felt on the defensive in the culture wars. The once-solid Democratic South crumbled under the weight of civil rights, while fundamentalists bolted over issues like feminism, choice, gay rights and the sexual revolution. The politics of protest in the late ’60s alienated a segment of blue-collar America from the party. At least that is how it felt to Democrats.

At the same time, cultural progressives were leaving the GOP over their anti-choice stand, their closed-mindedness and their opposition to civil rights. The net result was to replace Democratic dominance with an even division nationally. States traded places, with some shifting from red to blue and others migrating in the opposite direction.

However, emerging issues like stem-cell research and end-of-life decisions, together with changing sexual mores, will create a culturally progressive majority.

The first flowering of this majority occurred during the Terri Schiavo debate, when America seethed with anger at Republicans who were denying people the autonomy to make decisions about their own lives. By a 40-point margin Americans wanted to allow Schiavo’s husband to remove the feeding tube that was keeping her in a permanent vegetative state. At a time when 48 percent approved of the president’s performance overall, just 34 percent approved of the way he handled this case.

The stem-cell debate reprises the Schiavo controversy, as here too overwhelming majorities take the culturally progressive position. Over the past couple of years, polls have shown 56 to 71 percent in favor of stem-cell research. Indeed support is strongest in response to questions where arguments are laid out on both sides of the issue. For most Americans, the ethical imperative is finding cures for deadly and debilitating diseases.

Stem-cell research has the characteristics of a transforming issue. It is important to voters, reflecting their fundamental values. During the last presidential election, it was among the most widely discussed topics on the campaign trail. Gov. Jon Corzine (D) demonstrated its political power, using the issue heavily in his victory last fall in New Jersey. It has already become a major electoral issue in the races for Wisconsin governor and Missouri senator, among others.

The GOP itself is wracked with division at both the elite and mass levels. In almost every recent poll, majorities of Republicans support the use of these lifesaving techniques. Senate Republicans, who usually march in lockstep with the President, are also divided. Even Bill Frist and Orrin Hatch are bucking Bush.

But most Republican members are poised to oppose stem-cell research, and President Bush plans to exercise the first veto of his administration to stop scientific research that could provide cures for Parkinson’s, Alzheimer’s, diabetes and spinal-cord injuries.

Thus the Republican Party will stand firmly on the side of discarded embryos against medicine, against science and against cures for diseases that are the scourge of tens of millions of Americans. By any reckoning, the GOP will be on the wrong side of this cultural divide.

As lifesaving treatments begin to emerge from this branch of medical science, the Republican stance will look even more foolish than it does today.

Mellman is president of The Mellman Group and has worked for Democratic candidates and causes since 1982, including Sen. John Kerry (D-Mass.) in 2004.