While Washington searches for ways to weaken Iran’s murderous rulers, our supposed NATO ally Turkey is working overtime to keep the mullahs alive — and in power. This week’s diplomatic tug-of-war over US-Iran negotiations is a win for Recep Tayyip Erdogan, Turkey’s Islamist strongman, who has led a cynical campaign to stall for time and block US and Israeli military action against the Islamic Republic after its brutal crackdown on civilian protesters. He’s feigning concern that military action would spark “regional instability,” but his real goal is simple: Keep Iran’s theocracy from falling — and stop the emergence of a...