I think these are all excellent points. Usually, the prudential judgment involved in voting seems like simple arithmetic (“1 million babies/year > x, where x = literally anything you can come up with”). This year, it feels more like multi-variable calculus.

I did try to give long-term consideration to the future of the party in Part 3. Suffice to say I share your pessimism.

I’m becoming less and less convinced that they should. I wasn’t sure even before Trump, and now? If the GOP (at the national level, particularly) is unwilling and unable to carry out any practical (and precious few symbolic) steps to further the abolition of abortion, then the cost of destabilizing the GOP is, frankly, negligible. We’d all like a Whig/Republican style shakeup resulting in a new party that actually does the important things: this seems unlikely, but it’s possible. With Trump as the GOP nominee, I’m pretty skeptical that voting for the GOP furthers any moral good in the long term, and in fact it probably does the opposite by buttressing a two-party system that only maintains our current abortion regime.

Do you have to weigh this against possible short term goods like maybe-Trump-won’t-appoint-his-sister-to-the-Supreme-Court? Sure. And I haven’t done the weighing yet. But even having to do the weighing in the first place is damning for the GOP.