Interestingly, that the Executive would take orders from the Catholic Church was the main paranoia surrounding John F. Kennedy's election. People rage over the Supreme Court using European precedent in their decisions, yet think that the President or Governor should be influenced by the decisions of the head of a European nation.
However, the teachings of the Catholic Church in this matter agree with Scripture. Any Christian, Catholic or not, who is confronted with the problem Jeb Bush faces should deal effectively to save Terri Schiavo's life. Furthermore, since the importance of preserving life is just a matter of common decency, any man who believes he is moral, of whatever faith, should be as compelled to do the same as a Christian.
This is not following the dictates of a religious leader living in Italy. This is following the dictates of one's conscience guided by Scripture or the rules of decency and compassion for others.