Boston ? Who would have dreamed that stem cells would rise above their microscopic stature to become stars on the political stage?

Until now, science has rarely made an appearance on a party platform. Indeed, no campaign manager has ever before said, “It’s the stem cells, stupid.” But this year, there is a new biotech front in the culture wars.

It isn’t just that stem cells got huge applause the 20 times they were mentioned on the Democratic convention podium. There was the way Ron Reagan ended his masterful speech with the call: “Whatever else you do come November 2, I urge you, please cast a vote for embryonic stem cell research.” Who knew the little pre-embryos were even running?

This was, needless to say, a poll-tested subject. An NBC-Wall Street Journal poll showed more than 70 percent of voters — and 58 percent of Bush supporters — approve of using embryonic stem cells for research. That’s at least 10 times the number of voters who can actually define a stem cell.

A little background, please. These cells, harvested from five-day-old fertilized eggs, may offer the best hope for treating some pretty awful diseases. But the pro-life opposition believes that a fertilized egg is a human being. One side’s hope for a cure is another side’s murder.

In the summer of 2001, George Bush gave his very first speech to the nation on federal funding for this research. In a compromise that satisfied virtually no one, he declared that the government would only fund use of a limited number of stem cell lines already in existence. To make a very long story short, publicly funded research has been pretty well crippled.

Meanwhile, a growing number of folks — even those who consider themselves pro-life, even Orrin Hatch — can’t figure out why it’s OK to have fertilized eggs permanently ensconced in a fertility clinic freezer, but not OK to use them to find a cure for diseases.

The whole matter of embryonic stem cells gets easily tangled up with other issues, like cloning. When Ron Reagan did his Cliffs Notes version of stem cell science, few noticed that he was talking about therapeutic cloning. Everyone got it when he asked, “How’d you like to have your own biological repair kit standing by at the hospital?”

We’re still a long, long way from having a Fix-It Kit for, say, Christopher Reeve. But we’re beginning to understand that the politics of the religious right may be in the way of alleviating pain and suffering, diabetes and Parkinson’s. Embryonic stem cell research has become the stand-in, the designated hitter, if you will, for the struggle between science and ideology, moderates and extremists.

This is how Reagan framed the debate: “Surely we can distinguish between these undifferentiated cells multiplying in a tissue culture and a living, breathing person — a parent, a spouse, a child.” It’s not a question of whether the pre-embryo has any moral worth, but whether it has more worth than a person.

Does this resonate with long-raging abortion wars? Of course. Those who believe in a woman’s right to decide also distinguish between an embryo or early fetus and a living, breathing person: a pregnant woman. Abortion, however, is a word that, unless my ears failed me, was never spoken on the DNC podium.

So stem cells are also stand-ins for the abortion debate. They demonstrate what’s at the core of pro-life rhetoric and its implications.

As bioethicist George Annas puts it, “The anti-abortionist will say that the embryo has the same status as a child and taking an embryo apart for harvesting the stem cells is the equivalent of taking a child apart for its organs. That’s the most anti-science argument I’ve ever heard.” Imagine instead, he adds, if an IVF clinic were on fire. Is there anyone who would save the fertilized eggs in the freezer instead of a child?

When the Republicans arrive in New York, I’m sure they’ll want to talk about so-called “partial-birth abortion.” But stem cells are the wedge with a Democratic label. The issue allows pro-choice candidates a chance to show the ideology of their opponents and plant a question in the minds of the undecided: “Who are these people?”

Who are they? The same folks who de-funded the United Nations population program, stacked the science panels, fought emergency contraception, and look forward to overturning Roe v. Wade.

It’s just that somehow or other, it’s easier to see them as they hover around a powerful and promising little cell.

Ellen Goodman is a columnist for Washington Post Writers Group.