1. I'm on what's conventionally labeled the "incrementalist" side of the prolife movement (in contrast to abolitionists). However, I don't think casting the issue in terms of incrementalism v. immediatism is the best way to frame the issue.
As I understand it, the usual claim is that incrementalists share the same goal as abolitionists. Both sides aim to eliminate abortion entirely. But they differ on strategy and tactics.
2. I think incrementalists take this position in part because they are put on the defensive by abolitionists. Imagine if the incrementalist said, "As a matter of fact, eliminating abortion entirely is not my goal".
i) Is that a damning thing to say? Well, that depends. The statement is ambiguous. It could be taken to mean I don't think we should eliminate abortion in toto. In general, that would be a morally deficient position–although even most hardline prolifers make some exceptions (e.g. ectopic pregnancies).
ii) However, we need to distinguish between goals and ideals. A prolifer might say eliminating abortion in toto is the ideal, but not the goal, because that's an unattainable goal. Is that a scandalous thing to say?
Suppose a doctor has a patient in the early stages of MS. Is it the doctor's goal to cure the patient? No, because he doesn't have a cure for MS. Imagine if the patient became irate: "What kind of doctor are you that it's not your goal to cure me!" But that's no fault of the doctor. It's not his goal to cure the patient because he's in no position to cure the patient. It can be the goal of a medical researcher to find a cure for MS, but not the average physician.
3. That said, there can be value in having ambitious goals. One rationale for having ambitious goals is that if you aim higher, then even if you fall short of your goal, you may come closer to the goal that if you lowered your expectations.
Take an Olympic athlete who thinks he has a shot at winning a gold medal or breaking a record. He may push himself harder, and have a better chance of success, by aiming higher.
Or take an underdog sports team that's up against the best team in the league. The opposing team is undefeated. So the odds are stacked against the underdog team.
If the underdog team goes into the game with a defeatist attitude, that's a self-fulfilling prophecy of doom. A defeatist attitude is self-defeating. It pretty much ensures failure.
If, however, the underdog team aims high, it might score a surprise upset. Perhaps the opposing team was overconfident. The opposing team didn't bring their best game to the competition because they thought they were unbeatable.
4. However, it really depends on the examples we use to illustrate the principle. It's easy to come up with counterexamples where an ambitious goal is foolhardy. Suppose your goal is to graduate from Harvard med school. Suppose you don't have the chops to compete with the cream of the crop. You are no match for your classmates. As a result, you wash out of Harvard med school with humongous student loan bills.
Suppose, if you aimed lower, you could graduate from a perfectly reputable, but less prestigious med school. By aiming too high, you missed out on both. You flunked out of Harvard, and you blew the opportunity to become a physician by attending a less demanding med school.
In addition, some Harvard students commit suicide because they just can't cut it, and they are too ashamed to face their pushy, ambiguous, disappointed parents.
To take another example, some competitive athletes suffer injuries at the gym. They push their body to the limit, hoping their body will adapt, but they push their body beyond the limit. They suffer injuries that require surgery. As a result, they may never get back to where they were before the injury.
And they weren't injured in the game. They didn't get to that point. This was conditioning to prepare themselves for the game, but as a result of the injury, they had to drop out.
So overly-ambitious goals are counterproductive. You don't end up with more. You end up with less–or nothing at all. Indeed, you may be worse off than when you started.
5. One of my concerns with making the total elimination of abortion the goal is whether setting the goal there is the justification for opposing abortion at all. Does the warrant or rationale for saving babies depend on having as a goal the total elimination of abortion? Is it not worth the effort if that's an unattainable goal?
To take a comparison, historically, Christians have been in the vanguard of founding orphanages. Should the goal be to have enough orphanages to care for every abandoned child? Suppose we lack the resources for that laudable project. Imagine someone setting a quota or threshold: unless we can save all orphans, or 90%, we won't build any orphanages! Let them all die on the street!
Rather that stipulating an artificial goal, we should just do as much as we can. Saving babies isn't predicated on the prospects of winning, as if it's not worth the fight if you lose. You do the best you can. To revert to the illustration, if you can only save a fraction of abandoned children, that's heartbreaking, but it hardly means you throw in the towel and refuse to save the few you can.
6. We should distinguish between targets and goals. Instead of having a utopian goal which may or may not be attainable, we should have targets. Not making the total elimination of abortion your goal doesn't mean you stop short even if you were making steady progress, and could achieve even more reductions in abortion.
We don't know what the future holds. If you secure one target, you move onto the next target. One might say the elimination of abortion is the goal if it's possible to eliminate abortion. If it's not possible to eliminate abortion, then that's not the goal. There's no obligation to pursue or commit to impossible goals. A problem with a setting hard-n-fast goal is that we don't know in advance if that's attainable.
7. Abolitionists accuse incrementalists of faithlessness, but there's no biblical promise that God will eliminate all or most evil during the church age. There's no biblical promise that God will eliminate murder during the church age. To some extent we find out what's possible by doing what we can.