One may use deadly force against an adult, at least in some states, even when one's life is not at stake. Should states not have the authority to permit such?
Before a constitutional pro-life amendment can be ratified, it will almost certainly necessary for 38 states to have enacted strong pro-life legislation. States aren't apt to enact such legislation unless or until it becomes clear the federal government will honor their authority to do so.
Do you see any realistic means of getting a pro-life amendment ratified that would not first require states to be allowed to pass their own legislation?
If someone offers up a constitutional amendment, I’ll support it, providing it’s properly worded and treats all persons equally before the law. But that’s only useful as a means to clarify for those who can’t read the plain meaning of words. Our Constitution already contains the provisions to protect the unborn in the Preamble and the Fifth and the Fourteenth Amendments. All we lack is the political will in all three co-equal branches of government to enforce it.