I doubt anyone believes that abortion should be left to the states. SCOTUS said that the issue should be resolved politically as opposed to judicially, i.e., the U.S. Constitution doesn't create law on the subject. But considering how contentious the issue is, and how clumsily states have tried to prevent travel to obtain abortions out of state, a federal statute seems like the most reasonable source of political resolution. (I won't muddy the waters by saying what the federal statute should say.)

I believe that "Leave it to the states" is not a position that pro-life Republicans running for federal office support, but it is a way for them to duck the question of what a federal law would say. Because they are running for federal office, they are obliged, they will say, not to have an opinion on what the state law should be. But have no doubt that if they had the votes to ban abortion federally, they would do so.