You're wrong, as least as it pertains to doing what's right.
The Hegelian philosophical roots of such an idea are the same as those of Marxism-Leninism.
Incrementalism works just dandy for evil, but not for righteousness.
If you put poison in a cup of wine "incrementally," the result is a cup of poison.
If you put wine in a cup of deadly poison, even incrementally, you never end up with a cup of wine...it is and remains a cup of poison.
I've watched this process played out in the real world, in the pro-life movement, for years, and this is how things work in reality.
Is this really true, though? At some point in both examples the wine-to-poison ratio is the same (assuming a big enough cup). So, if the first cup isn't poison until x number of units has been added incrementally, then the second cup eventually becomes wine once you dilute the poison with a great enough volume of wine.
I don't mean to be pedantic. I do believe good people can be convinced to do wrong by increments more easily than evil people can be convinced to do right. But in the case of abortion, we're dealing with vast numbers of basically undecided people who may superficially buy into leftist arguments but don't really think about it that much. I believe these undecideds grow to embrace life by increments. I've seen this happen with a lot of people I know -- people who once were purely "pro-choice" see that babies as young as 21+ weeks can survive, and come to believe that abortion after that point is infanticide. Then they see their own babies' hearts beating on the sonogram at 7 weeks, or moving their arms and legs not too much later, and the line of what's acceptable moves back again. At some point many realize that all these lines -- seven weeks, fourteen weeks, 20 weeks -- are arbitrary. However, if you had hit them back before their 21 week realization with the fact that even embryos are babies, they would have outright rejected it. I believe the same thing happens with abortion law.
I'm not knocking you for your stance -- it's absolutely logically consistent. But I just can't see how we get there from here without convincing people state by state. What's the quickest path to protecting life on a federal level, in your view?