It's a question most pro-lifers have faced.

“What's the big deal about abortion? Why does this one issue loom so large in your mind, outweighing so many others?”

It's an excellent question. We don't want to seem like extremists — and we certainly don't feel like extremists — but the abortion issue does loom larger than all others in our minds.

But there's another question many of us have faced from our children: “Daddy, what's partial-birth abortion?”

It's another good question, and we struggle to answer it in a way that describes this procedure as monstrous without convincing our children that the “pro-choice” people we know are monsters.

The difficulty we have answering this second question goes a long way to addressing the first.

How to answer that second question fairly?

We can use recent court testimony and admit that those who perform abortions for a living don't call it “partial-birth abortion.” They call it “D&X” or “dilation and extraction.” They give a woman drugs to induce signs of premature labor. The child is then delivered feet-first. At the point when the head would be born — the most difficult part of birth — the child's skull is crushed with forceps.

Judge Richard Casey decided a partial-birth abortion case in New York. He called D&X abortion “gruesome, brutal, barbaric and uncivilized.” He established that the babies are moving up to the point that their skulls are crushed, and that these abortions “subject fetuses to severe pain.”

Then he said that Congress can't ban the procedure because the Supreme Court has ruled that this and all forms of abortion must remain legal.

If it's hard to explain why plain old first-trimester abortion is such a major problem to us, we can point out what the legal system has had to do to make abortion legal.

Since life begins at conception, courts can't point to a moment in the pregnancy where the unborn child is qualitatively different from what he was the moment before. So to protect abortion, courts have had to say that abortion at any time is legal.

Partial-birth abortion exposes abortion for what it is.

It exposes the emptiness of the slogan “pro-choice,” for what woman would consider partial-birth abortion an empowering “choice?”

In fact, most women who have abortions at all stages, when they are willing to talk about their abortion at all, don't talk about it as a choice. They describe it as a desperate act done because the father of the child or other family members refused to honor or support their pregnancy. One woman compared the decision to an animal chewing off its leg when it's caught in a trap.

Partial-birth abortion has tarnished the medical profession. “In no case involving these or other maternal health conditions,” wrote Judge Casey, could defenders of abortion “point to a specific patient or actual circumstance in which D&X was necessary to protect a woman's health.” And yet prestigious medical organizations defend the practice in the same ways they defend earlier abortions.

Partial-birth abortion has implicated the legal profession, as well. Courts had to do mental gymnastics to explain how even this form of killing can be legal under a constitution which was written by our founding fathers to codify the rights to life, liberty and the pursuit of happiness. In order to keep abortion legal, they had to make D&X infanticide legal.

So partial-birth abortion has made it clear: Pro-life voters aren't the extremists. “Pro-choice” voters are.

Saddest of all, in a self-governing nation in which the people vote for lawmakers, abortion implicates all of us who have voted for the lawmakers who protect its place in our law.

This November's presidential election does not pit a great hero against a great threat, as political propagandists on both sides would have us believe. Catholics can't be entirely comfortable with either candidate.

But it does pit a Democratic challenger who voted six times to keep partial-birth abortion legal — six times! — against the president who signed the nation's first law outlawing it and who says he wants to work toward ending abortion in the United States.

In the face of so grave an evil, what option do Catholics have, other than to vote for life? And in the face of this stain on our nation's honor, we should do all that is in our power to register pro-life voters and to educate other Catholics about this important issue.

This is one of several editorials addressing major issues at stake in the Nov. 2 elections.