Take a leap of faith. Assume Sen. Joe Biden is an intellectually rigorous man who never fails to act on his own convictions when he votes in the Senate -- and that he is especially careful in thinking things through when he votes on matters of life and death.

Now, try to entertain Joe Biden's logic -- on a matter of life and death.

"I'm prepared as a matter of faith to accept that life begins at the moment of conception," Biden said on NBC's "Meet the Press" on Sunday. "But that is my judgment."

Biden's implication is that it is equally plausible to conclude that life does not begin at conception and that this conclusion ought to command as much respect from rational people as the conclusion that life does begin at conception. For Biden -- if you take him at his word -- the question of when life begins is not determined by science but by religion. It is not only a multiple-choice question, but a question with multiple correct answers.

"It's a personal and private issue," he said. "For me, as a Roman Catholic, I'm prepared to accept the teachings of my church. But let me tell you. There are an awful lot of people of great confessional faiths ... who have a different view. ... They believe in their faith, and they believe in human life, and they have differing views as to when life (begins)."

Now, try applying Biden's reasoning to a mammal other than homo sapiens.

Try it with polar bears -- a species whose life is so highly valued by our political establishment that the Bush administration listed it as "threatened" even though its numbers have been increasing.

Let's say one religion says polar-bear life begins at conception; another, when the polar-bear fetus is viable; another, in the third trimester of polar-bear pregnancy; another, at polar-bear birth; and yet another, not even at birth -- if the polar-bear cub is disabled.

Of course, no organized movement is demanding a "right" to kill unborn polar bears, so no organized movement is promoting the propaganda that polar bear lives don't begin at conception, and so Biden does not have to be conflicted about whether to act on his own convictions about polar bears or someone else's. On "Meet the Press," Tom Brokaw -- in a half-hearted way -- challenged Biden on the contradiction between his affirmation that life begins at conception and his pro-abortion voting record.

"But if you, you believe that life begins at conception," said Brokaw, "and you've also voted for abortion rights --"

"No, what I voted (was) against curtailing the right, criminalizing abortion. I voted against telling everyone else in the country that they have to accept my religiously based view that it's a moment of conception," said Biden. "But then again, I also don't support a lot of other things. I don't support public, public funding. I don't, because that flips the burden. That's then telling me I have to accept a different view."

But Biden has in fact voted to force taxpayers -- no matter what their religion -- to fund the deliberate killing of human embryos, who Biden acknowledges are human lives.

On July 18, 2006, and on April 11, 2007, he voted -- along with Republican presidential candidate John McCain -- for the Stem Cell Research Enhancement Act. It ordered the Department of Health Human Services to "conduct and support research that utilizes human embryonic stem cells ... derived from human embryos that have been donated from in vitro fertilization clinics."

In other words, it said taxpayers who share Biden's understanding that life begins at conception must pay taxes to fund researchers who kill what Biden affirms are human beings. (The bill did not become law because President Bush vetoed it twice.)

The Stem Cell Research Enhancement Act had nothing to do with abortion. Biden needed to answer only two questions before voting on it: 1) should the government approve the deliberate killing of innocent human lives, and 2) should the government force taxpayers to pay for it.

Biden answered both questions: yes.

On July 25, 2006, Biden voted against the Child Interstate Abortion Notification Act. It prohibited "knowingly transport(ing) a minor across a state line, with the intent that such minor obtain an abortion, and thereby in fact abridge() the right of a parent under a law requiring parental involvement in a minor's abortion decision, in force in the state where the minor resides."

In other words, Biden protected the ability of a stranger to sneak a teenager across state lines to have an abortionist kill her unborn child, even if the teenager and her parents, like Biden, affirm that life begins at conception and even if they belong to a religion that teaches abortion is murder.

When it came to these issues of life and death, Joe Biden would not have forced Americans to bow down to his convictions, he would have forced them to bow down to someone else's.