Abortion is back with, dare we say it, biblical vengeance.

Republicans recently have been focused on Barack Obama's opposition several years ago to "born alive" legislation in Illinois that mirrored similar federal legislation aimed at granting personhood to a fetus/baby that was alive after removal from its mother's body, either by abortion or premature birth.

In the past few weeks, Obama has been accused of everything from favoring infanticide to lying about his vote, to inventing a cover-up, to being a baby-killing extremist.

Politics is no place for the squeamish.

What is more likely true is that Obama is studiously cautious, too smart by half, and ambivalent to a fault. Suddenly, the man whose campaign seemed helium-propelled is being pulled back down to Earth by the force of his own vagueness. Abortion, of all things, has become his kryptonite.

The long history of the Illinois born-alive bill is, well, long. Sixteen versions of the legislation came and went during the period under scrutiny and finally passed after Obama left for Washington. That history is also complicated and not as straightforward as is being advanced by Obama's and abortion's common foes.

It is probably fair to say that Obama does not favor infanticide, though his position on the Illinois bill was extreme even by pro-choice standards. But Obama's current problem isn't really about his position on abortion. It is about his central weakness as a presidential candidate: He overthinks and ends up seeming not to know what he thinks.

He can't seem to give a straight answer.

To briefly recap: Obama's initial opposition to the born-alive legislation was a concern that such a law would undermine Roe v. Wade. Based on his comments at the time, he apparently reasoned that granting personhood to an aborted fetus, albeit one with a heartbeat, was a subterfuge tactic aimed at granting personhood to a fetus.

Not without cause did he reach that conclusion. Most observers of the abortion debate understand that the legislation was fueled in part by hopes that personhood eventually might find its way back inside the birth canal. This may have been a tactic, but so it goes.

It has always seemed to me perfectly appropriate that we find terminating human life troublesome. Although settled as the law of the land, abortion at any point should be an unsettling proposition. The fact that abortion refuses to recuse itself from present politics merely confirms that many Americans are not ready to be gods.

Obama, perhaps, excluded. When asked to explain his position as a state legislator, Obama said he would have voted for the law had it included a neutrality clause -- similar to one added to the federal law -- affirming that the bill would not impact Roe v. Wade.

But the Illinois legislation in final form did include such a neutrality clause, prompting charges that Obama deliberately lied. Or did he merely misremember, as often happens in politics?

What did Obama mean and when did he mean it?

Alas, the more he tries to explain his position, the more muddled the picture becomes and the more confused voters are. The most revealing answer may have come when pastor Rick Warren asked the Illinois senator when a baby gets human rights.

"Well, uh, you know, I think that whether you're looking at it from a theological perspective or, uh, a scientific perspective, uh, answering that question with specificity, uh, you know, is, is, uh, above my pay grade."

Well, uh, not really.

Yes, Warren's question was complicated, especially if you're a politician afraid of saying the wrong thing. But the answer is really pretty simple. It's whatever one thinks. It is not above anyone's pay grade to be honest.

Instead, Obama punted.

Americans are accustomed to differing views on abortion and will tolerate a flip-flop now and then. But a politician who finesses or fudges out of an instinct to please will be viewed as either spineless or insecure or both -- none of which inspires confidence.

The result of such exquisite ambivalence isn't a higher level of discourse, but a lower level of trust, as recent surveys reflect. A new Reuters/Zogby poll shows McCain running five points ahead of Obama nationwide. Other polls show McCain pulling even.

Obama's born-alive problem ultimately could prove fatal to the man who thought too hard and lost his sense.