Rebecca writes (see comments section): "As a strategic means of ending abortion, unprincipled incrementalism has been a complete failure and got us the ruling in Roe v Wade."
At this point, I am going to have to pull rank on you. You really don't know what you're talking about.
First, Roe v. Wade is not the result of a strategy employed after Roe v. Wade. That is actually impossible, unless you believe in time travel and backwards causation.
Second, both the Human Life Amendment and the Human Life Bill of the early 1980s failed to pass. So, based on your reasoning, non-incrementalism is a complete failure, since each was a non-incremental approach.
The problem is how we judge success and failure. But none of us is ever in the position to make that judgment, since success may require literally centuries to undo the damage of the Enlightenment (which took about 300 years to unravel the moral foundations of Western Civilization). If anything, what we have seen over the past decade or so is a real shift in opinion from prochoice to prolife. And it happened after the partial-birth abortion debate and the Born Alive Infant Protection Act (BAIPA), both of which shifted the focus from "choice" to the nature of the unborn. The prolife movement was not going to have a chance unless it changed the question in the debate, which has been largely owned by the other side.
Think about the same-sex marriage advocates. They first began with decriminalizing homosexual acts, then moved to civil unions, and then once those were in place they raised the question, "So, what's the difference between these couples and different gendered ones?" That question could not have been asked in 1970 without snickers from even liberals. SSM is now a reality in at least five states.
Incrementalism is the only way to go, since it shifts the premises assumed by the wider culture making it nearly impossible to resist the next step. In the prolife case, that is precisely the strategy as well. If a child killed by PBA is protectable, why not the one killed by D&C two months earlier by a method no less brutal though its victim is smaller? Or the BAIPA. If the state must save the child who survives the abortion, why not a minute earlier, or a month earlier?
It's not always about what people explicitly believe. It's sometimes about what they implicitly believe and are eventually forced to concede given the trajectory of their worldview.
Incrementalism for its own sake is indeed counterproductive. But incrementalism for the sake of breaking new ground to push people in the prolife direction when they otherwise would not entertain it is ingenious.