Some readers of the Human Life Review might not want to hear what I’m about to say. If you’re a single-issue voter, be able to defend your reasons for taking that approach. If you can’t, think harder about your political philosophy. First, though, acknowledge that a single-issue voter is what you are, or have been. People who are tend to be reluctant to say so, even to themselves.

Political culture in America is colored by our two-party system, which leads to the frequent observation that our choices at election time are binary. But what is binary is the choice we make at the end of our deliberation. The deliberation itself, at least for most voters, consists of innumerable calculations, as we identify and juggle the interlocking interests and values at stake in the election. We weigh them, rank them according to importance, and consider how the various attributes and agenda items of a candidate or party would support or conflict with one another.

Single-issue voters are different in that regard. When the protection of unborn children is your lodestar, you favor the candidate whose record and rhetoric shows him to be more likely to promote laws that would restrict the availability of abortion. His integrity in the matter of supporting the pro-life cause affects your perception of his other policy positions and even of his character. You’re more likely to approve of them, to find reasons to agree with him generally, and to think that the core of his candidacy is defined by courage and other virtues that you associate with the pro-life movement.

Even on its own terms, however, the case for single-issue voting turns out to be complicated. As does the case against it.

A frequent objection to single-mindedness on the part of pro-life voters is that laws will be respected and enforced only to the degree that the public accepts them as reasonable and just. Of course, abortion policies that reflect a slightly more pro-life attitude than is supported by public opinion can serve a teaching function, nudging us toward greater respect for the unborn child, but they’re liable to provoke us to bolt in the opposite direction if they run too far ahead of where we are now. Some pro-life advocates fear that the Alabama bill banning abortion even in cases of rape or incest will prove to be counterproductive, pushing fence-sitters toward the side of unlimited abortion rights. If they have to choose between that and an outright abortion ban, many will take the former—and will be inclined to regard subsequent initiatives from the pro-life camp more warily.

Still, unpopular anti-abortion legislation could serve the pro-life cause even in the long run, if law enforcement can be trusted to enforce it. An increase in restrictions on abortion would not only save the lives of some unborn children now but would also establish facts on the ground—a baseline of societal norms to which most people would, in time, conform their ideas about the relative injustice of abortion. Initially, people would resent laws that they considered too severe, but they would get used to them, or their children would, or their grandchildren. That’s the theory, anyway. The risk is that, instead of subsiding, the popular resentment will persist and then grow.

Forcing an unpopular law on the public is a defensible tactic, then, but a questionable strategy. What may be good for the pro-life movement in Alabama in 2019 may be bad for it in America in the long run. Here we begin to recognize the limitations of single-issue voting.

How harmful to the pro-life movement in the long run is a political candidate who promises anti-abortion policies but makes no effort to persuade, or who in his rhetoric and behavior models attitudes that clash with the effort to build a culture in which people are encouraged to feel tenderness for unborn children? The relationship between the single-issue pro-life voter and the candidate who makes promises to him is asymmetrical. The candidate represents a bundle of ideas, causes, and sentiments. He promises to promote the sliver of those that are dear to pro-lifers, but in return he expects their vote for the whole package, his candidacy and the totality of what it represents.

Recently an Irishman and a Spaniard explained to me, each in his own way, that the center of political gravity in Europe has shifted to the left on social issues. Most center-right parties accept the current status quo on both legal abortion and same-sex marriage and civil unions. Although the newer, populist-nationalist parties on the European right do not consistently try to advance a social-conservative agenda, they tend to give it a place at their table, and so advocates for welcoming unborn children into the world find themselves in league with immigration restrictionists.

The practical differences between the two issues, immigration and abortion, are obvious, but so are their symbolic similarities. As a political matter, the drive to keep out the foreigner while ensuring that the unborn child will pass through the birth canal alive and intact is problematic. The dissonance registers with us, if only subconsciously. The concern to block immigrants from settling in our communities and competing with us for jobs, real estate, and other resources is one of the driving passions of our present political moment. How do we prevent the emotions that fuel our hawkishness on immigration from seeping into our disposition toward the unborn?

Whether to support or to oppose a candidate whose music clashes with his lyrics on abortion comes down to a prudential judgment. It will differ from one person to the next. Let’s presume that each of us arrives at his binary choice—between a Democrat and a Republican, typically, here in the United States—in sincerity and good faith.