The Same way people view slavery today will be similar to how abortion will be viewed as later
While I disagree with this on so many levels, it is definitely interesting to look back at the beginning of the pro-life movement. It's supporters absolutely branded themselves as the ideological descendants of the abolitionists, arguing that the characterization of fetuses as less than human and undeserving of full rights was eerily similar to how proponents of slavery spoke of Blacks ("Northern Republicans care so much about these slaves but couldn't care less about starving Irish immigrants in NYC" isn't a dramatically different criticism in style than "Republicans are pro-life until the baby leaves the womb, then they don't care").
Again, I do not adhere to the comparison. At all. But it's worth noting that that's how they felt.
Many still argue it that way.
It wasn't quite as "in" for Democratic partisans to push the party-switch narrative back then, so I think it was a more respected comparison.
Was it always that the Republicans were the pro-life and the Democrats were the pro-choice party? I know that by 1984, that was the case.
Nixon, Ford, and H. W. were all at one time or another pro-choice.
W and Trump were, too.
Trump, yes, but W has been pro-life throughout his whole public life.