Well, they've nailed Bill Frist. The Senate majority leader let himself get caught proclaiming both the sanctity of human life and his opinion that maybe we ought to expand embryonic stem cell research.

Whatever else you think of the Tennessean (and physician), doesn't his newest position -- that more of the embryos left over from fertility treatments should be made available to researchers -- paint him as morally inconsistent and perhaps even hypocritical?

For whatever comfort it may be for Frist, I say: me, too. Maybe most of us. Life's difficult questions almost always produce a measure of inconsistency -- otherwise they wouldn't be so difficult.

I'd like to have $100 for every American who espouses the sanctity of human life and still believes in the death penalty. Catch them in their little inconsistency and they'll say that embryonic stem cell research would destroy innocent life. So go ahead and ask them about their support of the war in Iraq, which, whatever its ever-shifting justifications, has taken uncounted innocent lives from the moment of the very first U.S. bombing raid.

Not for nothing did Emerson dismiss (foolish) consistency as "the hobgoblin of little minds."

Frist, to return to the issue at hand, found himself the darling of right-to-life advocates (and of the political right in general) when he took the position that the estimated 78 stem cell lines President Bush cleared for research in 2001 would be enough. The senator said last week that, since perhaps only 22 of those stem cell colonies have turned out to be usable for research, he had changed his mind. He would now support a House-passed bill that would allow research on stem cells from frozen embryos that would otherwise be discarded.

His critics now see him as a deserter -- and perhaps even a liar. Didn't he declare, when it suited his purposes, that life begins at conception? How can he also believe that it's okay to kill little children in pursuit of science?

But the science is tantalizing -- even, for some of us, irresistible. Stem cells, before they mature and become highly specialized, have the ability to become essentially any part of the human body. This fact has led scientists to hope that they may be able to use stem cells to regenerate spinal cords and portions of the brain and other bodily organs, thereby curing a host of irreversible afflictions, from paralysis to Alzheimer's.

Now, tell me you could perform these miracles if only you were allowed to raid the local hospital nursery for likely newborns, and I'll help hold you until the authorities arrive to lock you up. But tell me that there's a pretty good chance you can do it with frozen embryos that, realistically, will never grow up to become someone's little darling, and I want to think about it. Tell me that these frozen embryos are almost certain to be destroyed (or to become useless for either laboratory or nursery) and I'm all the way with Bill Frist.

Is it a foolish consistency to refuse to differentiate between toddlers and fertilized ova? Or is it hypocritical to imagine that those embryos, who are what you and I once were, only chillier, are something other than very tiny children?

Reaching the Frist conclusion doesn't end the issue, of course. Suppose it turns out that science is able to derive most of the benefits of stem cells from adult cells. Won't that mean they'll have sacrificed a bunch of babies for nothing? (Some scientists say that is unlikely, while others say we may learn from stem cell research how to make mature cells adaptable.) More realistically: Suppose stem cell research remains promising but turns out to be a longer-term process than we thought? Suppose, that is to say, we go through all the available stem cell lines without curing juvenile diabetes or Parkinson's. Where would we get more cell lines for research?

Would some future Bill Frist (or Bill Raspberry) countenance the deliberate production of embryos for research? Is there some bright-line ethical distinction that we can agree on? Or have we -- most of us, anyway -- already passed the point of no return?

Difficult questions -- unless you opt for consistency. Then you need only assert that, zygotes being human beings and killing human beings being unallowable, the seeming difficulties evaporate.

All that's left is to organize a posse to raid the local repository and free those pitiful children from their liquid nitrogen prison.