The Constitution is explicit about the equal protection of the right to life of each and every innocent person, in every jurisdiction.
You have to be trying to miss it to miss it.
“No person shall be deprived of life without due process of law.”
“No State shall deprive any person of life without due process of law; nor deny to any person within its jurisdiction the equal protection of the laws.”
The Constitution does a lot of things. Current law and the interpretation of the USSC (the one created by the Constitution) says abortion is legal.
Doesn’t make it right or moral, but it does make it legal.
There are limits to the power of the President. His job is to enforce the law, not make it. So you can issue any proclamation you want but they will be contrary to current law.
So what will you do when nobody pays attention to your proclamation because to do so would be illegal?