Less than a month ago, French President Emmanuel Macron staked his claim as the flag-bearer for globalism. In a speech to 60 world leaders at the Arc de Triomphe, he eulogized the United Nations and declared nationalism the "betrayal" of patriotism.

Last Saturday, tear gas and cobblestones flew in the same part of Paris as protesters trashed the iconic monument and demanded Macron's embattled government withdraw a proposed fuel-tax increase. For the first time in his presidency, he backed down. It was a humbling moment for opponents of the populist revolts that spawned Donald Trump.

Europe has seen many a critical juncture in recent years, from the Greek debt crisis to the anti-immigrant backlash against refugees and Britain's Brexit vote. Rarely, though, have so many political vultures been circling around one leader with so much at stake for the world order.