I believe many pro-lifers would be satisfied with the prospect that some other states make abortion legal so long as their own state bans it. This would include pro-lifers who recognize that the Constitution is silent on the topic of abortion, so no branch of the federal government is delegated the power to ban abortion across the entire nation.
This was my initial thinking on this subject as well, but I'm not sure I believe it anymore. If someone genuinely believes abortion is child murder, why should they be satisfied with a situation where babies are being killed in California but not Tennessee?