In his first State of the State address, Gov. Eliot Spitzer called for a $2 billion 10‐​year bond initiative for research and development, at least half of which would be set aside to pay for stem cell research. And in New Jersey, Gov. Jon Corzine has urged legislators to pass a bill asking voters to authorize adding $230 million to finance the same type of research over seven years.

Supporters of stem cell research applaud these governors for following in the footsteps of California, but if what’s happened there is any indication, they shouldn’t.

Mr. Spitzer and Mr. Corzine are right to support stem cell research — but not financially. Beneath the characteristically caustic debate between liberals and social conservatives, the truth is that stem cell research of all kinds, whether adult, amniotic or embryonic, accomplishes much more when it is left up to the private sector, which can pursue it without as many political and financial hindrances.

Supporting research through government money often requires broad agreement between groups that disagree bitterly, so not surprisingly, recent history shows that government tends to slow down medical developments instead of speeding them up.

Of the $3 billion over 10 years that Californians dedicated to stem cell research under Proposition 71 in 2004, not a single penny has been spent. Thanks to a variety of administrative problems and a pending lawsuit financed by groups like the Life Legal Defense Foundation and Focus on the Family, the money remains tied up.

Even where political consensus can be reached, government‐​financed research is enormously wasteful and bureaucratic. In California, once bonds are issued to raise the promised money, residents will end up paying an additional $3 billion in taxes to cover interest and related costs over three decades, when private research could have proceeded with no debt at all. Both the proposals in New York and New Jersey would also entail bond issues with huge interest burdens.

At least one state has gotten it right. During the last election, Missouri voters passed a constitutional amendment protecting the right to pursue all forms of stem cell research allowed under federal law, creating a haven for advanced laboratories. There was no state financing included. Within days, the Stowers Institute for Medical Research, which had raised $2 billion, put to work an international team of stem cell researchers it had assembled in anticipation of the amendment’s passage.

Medical research and development do not grind to a halt when government declines to support them. As a former Health and Human Services secretary, Tommy Thompson, said at a meeting of biotech industry leaders in December, 80 percent of all of the world’s medical research is done in the United States, in spite of more generous government subsidies in some countries.

According to The Journal of the American Medical Association, the amount of money for biomedical research in the United States increased to $94.3 billion in 2003 from $37.1 billion in 1994, and only 28 percent of that money came from the National Institutes of Health. Furthermore, data reported by the journal and by the National Science Foundation indicate that in areas where public financing remained the same or declined, the private sector stepped in and increased its share of research spending.

That’s exactly what happened 30 years ago, when the federal government — also for ethical reasons — refused to financially support in vitro fertilization research. The research went forward privately, and today, reproductive technologies represent a $6‑billion‐​a‐​year industry in the United States alone.

Whether or not someone supports embryonic stem cell research from an ethical perspective, he should oppose subsidizing research that could potentially bring billions in profits to the biotech industry. There is no reason that private companies can’t invest in their own research and development; they do it all the time, though one can understand their desire to have taxpayers foot the bill.

If the federal government must be involved, it shouldn’t insulate companies from the financial risks of developing new therapies. It should do what Missouri did: promise to stay out of the way and let research proceed regardless of political whims.

Government financing, after all, comes and goes with the politics of those in power. Private money, by contrast, comes and goes depending on the progress of the research and the likelihood of success.

Scientists should spend more time seeking private assistance and less time lobbying for government support. If there is a need, and if there is a way, the private sector will do it and do it much more efficiently than government would.

Stem cell research holds more medical promise than any scientific breakthrough since Francis Crick and James Watson discovered the structure of DNA, and it should be explored with all the enthusiasm and ingenuity the scientific community can muster.

All Governor Spitzer, Governor Corzine and company need to do is keep it legal, and get out of the way.