Trump's failed strong-arming of allies on Iran shows that pressure is losing its effect

Now he’s demanding — not just requesting — that they send warships to help the U.S. unblock the Strait of Hormuz, through which a fifth of the world's traded oil passes — essentially mop up behind the conflagration that he and Israel ignited in the Middle East. China, which is not an ally but was also asked to help, is ignoring Trump's call. Trump has singled out the refusal from the United Kingdom.