There’s nothing wrong with an incremental approach, per se.
The problem is when your incrementalism includes the codification of permission in the statutes to murder individual persons. All of them, as long as your illogical, unreasonable, arbitrary requirements are met.
There is a simple two part test of all legislation:
1. Does it recognize the God-given, unalienable nature of the individual right to live?
And
2. Does it provide the equal protection for every innocent person that the Constitution absolutely requires?
If it fails on either hand, it is immoral and unconstitutional, and in fact is reinforcing the practice of abortion on demand.
The problem is though that any law proposed that would satisfy the two tests you outlined has no chance of succeeding in its stated goal, which is (presumably) the end to all abortions.
It has no chance in doing that not because it has little chance of ever being enacted (even though that’s true) but it also doesn’t have a chance of succeeding because the current social environment isn’t convinced (as a general rule) that each fertilized egg is a person. After all, look at the practice of in-vitro fertilization for example. That entire barbaric and selfish process treats fertilized eggs as commodities that, if the time “isn’t right” can be put on hold, in an indefinite suspended animation hovering just a few degrees above absolute zero. Think about that for a second: thousands of babies are, right now, frozen in time, languishing in a man made limbo all because some “parents” thought it was their “right” to have a child at 50 years old. And that’s just the case with IVF!
No this culture (if it can even be called a culture) isn’t ready to state a fertilized egg is an individual with just as many rights as you and I, so the test #1 you describe would eventually fail, in the minds of many people, not just lawmakers. And as I’ve described (and I think you agree) laws alone don’t change people’s hearts.
If people’s hearts aren’t changed, then all the laws in the world won’t be worth a hill of beans in saving the unborn. And this includes the most moral and “constitutional” law.
And we can make the best, most impassioned arguments on the planet for why abortion is wrong, but THAT won’t mean a hill of beans either, if we don’t at least try something now that has a chance of succeeding: succeding to save at least some babies.
It’s a “glass is half empty or full” question really. I prefer to think of the legislation proposed these days that have a reasonable chance of success as saving some babies. Not “letting some babies die”. Again, half glass empty or full? This is the unfortunate position we find ourselves in today because of moral decay.