Boston ? Do you remember when Ron Reagan ended his Democratic convention speech with a rallying cry for political science: “Whatever else you do come Nov. 2, I urge you, please cast a vote for embryonic stem-cell research.” Who knew that the little pre-embryo was even running for office?

When the campaign is over, embryonic stem cells will win the prize for the smallest issue with the largest impact. You can’t even see these cells in the lab without a microscope, but in politics they’re looming larger every day.

After the star turn at that convention, stem cells have been center stage at partisan events and had featured roles in the presidential debates.

It’s rare that science ever gets on the political agenda, but stem cells came into this election laden with all the baggage of the abortion argument. The cells harvested from 5-day-old fertilized eggs are widely believed to offer hope for curing diseases such as diabetes and Parkinson’s. But the pro-life opponents have declared that the eggs are human and harvesting them is murder.

Three years ago, the president attempted a compromise by approving federal funding for a limited number of stem cell lines that already existed. The lines were too flawed and too few, the compromise flopped and the federal research stalled.

Now the debate has become a stand-in for the controversy about religion and science, extremists and moderates.

But there is a place where voters can literally cast a vote for embryonic stem cell research: California.

A group of citizens there have put Proposition 71 on the November ballot. It would create the largest-ever state-sponsored scientific research program. Bigger than the human genome project.

Prop 71 is, as one editorial writer said, a Bronx cheer directed at the White House. It’s the way a blue state can thumb its nose at a red president. As Robert Klein, a leader of the effort, says, “We can run a substitute national program.” This week, even Gov. Arnold Schwarzenegger gave his blessing to the initiative.

But even someone in favor of stem cells has to ask: Is this any way to run a science program?

This is the cost of thumbing that nose at the White House. The 30-page proposition would give $3 billion of public money to researchers — $6 billion if you include interest — over 10 years in a state that is cutting back on everything else. It would provide a constitutional right to stem cell research in a state without a constitutional right to health care.

As ethicist Lori Andrews says, “It’s offering the worst of both worlds. It’s asking the public to pay the check but leaving an unregulated biotech sector.” And it would fund biotech research without promising any return to the public that paid for it. Not even for treatments that are bound to be extremely expensive.

This is the price tag of a Bronx cheer. The research in California is not about using spare embryos from in vitro clinics, but about cloned embryos. More troubling, says Andrews, is the researchers’ attempt to “exempt themselves from laws on human subjects, including informed consent.”

Finally, under the strictures of the bill, the state can only fund what the federal government isn’t funding. What happens to the money if Kerry wins and we have, finally, a saner policy?

“I think it is respecting life to reach for that cure,” says Kerry. We have to reach for it. In defining stem cell research, Ron Reagan said, “Surely we can distinguish between these undifferentiated cells multiplying in a tissue culture and a living, breathing person.” But we can also distinguish between a solid and a shaky proposition.

The Bush administration’s policy created a strange two-track ethical code. The president froze federal funding on the grounds that embryos were human beings. But in the private sector, venture capitalists were left virtually unregulated.

Now Harvard University has only to ask its own university review board for permission to clone embryos for research. New Jersey has established a research facility of its own. And Californians are being asked to vote — up or down — blue or red.

I understand the urge of California to go it alone. I share the frustration and the desire to thumb my nose at the White House. With 35 million people, the state of California is the size of a separate country. But in the pursuit of science it isn’t a separate country.