2/3rds to pass?
the GOPe doesn’t want it to pass. They could have added it as a rider to something else with a bare majority if they really wanted it to pass.
I’m guessing it needs 2/3rd to pass so the POTUS can’t Veto it.
But all the pro-life organizations are fighting for this for a reason, which certainly shows it’s worth our time in making a phone call.