Your glorious Catholic "monarchs" in Belgium and soon in Spain have allowed laws with abortion on demand as well as homosexual marriage. Wake up and smell the coffee -- Catholic monarchy is neither a panacea for modern problems nor is it remotely practical, at least in the United States.
When abortion was legalized in Belgium in 1990, King Baudouin, a devout Catholic, temporarily abdicated rather than sign his name to the law. If he had been an "unconstitutional" monarch with real power, abortion would still be illegal in Belgium.