"If you don't have a heartbeat on this side of the uterus, you are considered dead. The same should apply for the other side."
I think that's a pretty good point. I'd add that sometimes brain function is also used as a determiner for "life" (or at least whether or not that "life" is worth "living"). And then there's the bible, using what we know as "breath" :-D. Personally, I think you are only fully "alive" when you've received your first spanking (from a qualified MD), just the way God wanted it to be.
It would be so nice to see America come to a reasonable compromise in the issue and be done with it. Most 1st world countries have a cut-off date for allowable, lawful termination of pregnancy; and only make exceptions beyond that date for the life or health of the mother.
Maybe someone from Canada or Europe can help me out here, but in most countries, they don't re-argue this issue every damn election, do they?