I've read the Constitution ("...to secure the Blessings of Liberty to ourselves and our Posterity..."). I've read about the separation of powers, where the judicial branch doesn't write law. I've read memo excerpts from SCOTUS justices where they blatantly stated that (at least) part of the Roe v. Wade decision was "legislative" and "arbitrary." I've read subsequent decisions where some SCOTUS justices admit that Roe v. Wade was a bad decision, but they leave it be, for the sake of continuity.
Committing abortions is not legal. It's tolerated and advocated, but that doesn't make it legal. Not under our Constitution anyway.