You will never get language (time limit) both the liberal and right of center states can agree upon so a constitutional amendment isn’t happening. Federal law is your best bet.
If your best bet on such a contentious topic is an inherently precarious social norm made from tenuous compromises then there will always be a lack of surety equivalent to only having a personal freedom being protected ~50% of the time or in some subsection of the country, depending on which party is in power. I don't think you can settle for that in the case such monumental personal freedoms.
I agree that strategically an amendment is unlikely, but a federal law, while better than nothing is still insufficient.
I do want to be able to reach a certain consensus rather than a compromise. It seems like there is a general consensus about abortions in cases of rape, incest, or for the imminent safety of the host. I also believe there is relative agreement about terminations earlier in the pregnancies rather than later, though I think Republican representatives went quite overboard in a number of their states' limits to that time window, past the sentiments of many of the constituents who may have voted for them.
P.S. since the Republican Party is so unabashedly resurrecting zombie political positions like states rights' in this fight, I wouldn't put it past them to try and rehash the Nullification crisis if a federal law on abortion were passed.
