“Can a Catholic in good conscience vote for a politician who is pro-choice?” This question always comes up around election time, which itself suggests that the question typically should get the answer “no.” We wouldn’t otherwise be bothered by it.

There are debatable cases. The town dog-catcher won’t decide anything about babies or abortion -- so maybe one could vote for the pro-choice candidate? Maybe; but also maybe the pro-choice guy wants to run for mayor after he wins as dog-catcher. Why give him a leg up?

For congressmen, who could vote for a constitutional amendment; senators who confirm Supreme Court justices and presidents who appoint them, there seems much less room for debate.

The “no” answer is disappointing to some because it seems constrictive. Nearly an entire political party gets eliminated. Yet whose fault is that -- the “plain man who votes in good conscience,” or the political party that has made abortion-on-demand an essential plank in its platform?

Also, if it became clear that the “plain man” ruled out that party’s candidates from the start, how many election cycles do you think it would take for the party to change its platform?

Suppose half the food sold in the grocery store contained poison, but shoppers kept buying it anyway -- could it be a surprise if the food selection never became uniformly wholesome? People might think, “We’re just stuck with poisonous food, I guess. All the foods I like have poison in them.” But aren’t we responsible for that when we have a choice and keep buying the poisonous food?

It’s a worry, I agree, that single-issue voters are open to manipulation. It seems that a candidate only needs to proclaim his support on that one issue, and he wins your vote, no matter what. And then once elected he doesn’t actually need to do anything -- since you’re a captive voter.

But you’re a captive only if there is no alternative; and, as we saw, there is no alternative just so long as voters signal that they’re open to voting for candidates who are pro-choice. That is to say: those voters who continue to vote for pro-choice candidates are the enablers who make it possible in the first place for politicians to manipulate the “plain man voting in good conscience.”

Let’s not castigate the “plain man in good conscience” for being simplistic, when he’s only acting as he should. Let’s rather reserve our criticism for those Catholics who, through their poor citizenship, expose their brothers and sisters to manipulation.

Poor citizenship? Isn’t that dogmatic and harsh? Shouldn’t I presume goodwill among those who disagree with me, just as I’d expect them to show goodwill toward me?

As to goodwill, ask yourself: Do you preserve goodwill throughout every moment of the day? To everyone you meet? In every situation? But if goodwill is not an absolute constant for you in a single day, why should we think that it holds for everyone in everything that they hold? Can’t goodwill ever fail? And if it ever fails, why not here?

I won’t trot out the clichés and ask whether it was in goodwill that slaveholders kept their slaves or Nazis shot their victims. Let’s just say that goodwill in the vague sense of confused good intentions amounts to nothing, precisely because everyone has it.

I’m more interested in the goodwill that naturally results in good for others (what else could goodwill actually be?) and I fail to find goodwill in that sense in someone whose policies lead directly to bloodshed and smothered consciences on a grand scale. While we are looking together at a picture of a dismembered fetus, try to explain to me how someone who supports that as the exercise of a right has goodwill.

For all its faults, the statement by the American bishops on voter responsibility, “Forming Consciences for Faithful Citizenship,” makes an important clarification about single-issue voting. The phrase, “single-issue voter,” according to the bishops, is ambiguous: the meaning changes depending upon whether we regard the single issue as guaranteeing or forfeiting one’s vote.

Catholics should not be single-issue voters in the first sense; that is, “a candidate’s position on a single issue is not sufficient to guarantee a voter’s support.” Nonetheless, Catholics should be single-issue voters in the second sense; that is “a candidate’s position on a single issue that involves an intrinsic evil, such as support for legal abortion or the promotion of racism, may legitimately lead a voter to disqualify a candidate from receiving support.”

A single-issue is, strictly, a disqualifying issue, because it involves a policy that would destroy something essential to the well-being of a free society. For instance, someone who supported slavery or segregation as a matter of principle has adopted a position which, because of its destructiveness for a free society, disqualifies him from reasonable consideration for office.

Nothing changes if lots of others hold the same thing -- except that those others thereby disqualify themselves from reasonable consideration as well.

The Church teaches, sensibly, that “those who are directly involved in lawmaking bodies have a grave and clear obligation to oppose any law that attacks human life,” and that “a well-formed Christian conscience does not permit one to vote for a political program or an individual law which contradicts the fundamental contents of faith and morals.”

But in regard to voting for someone who supports or votes for such laws -- in a representative democracy, how is that different from supporting it oneself?

Michael Pakaluk is a professor of philosophy and the director of integrating research at the Institute for the Psychological Sciences in Arlington, Va.