While world leaders gather in Katowice, Poland, for the COP24 climate summit, protesters in the streets of Paris have successfully forced French President Emmanuel Macron's hand, undercutting his efforts to impose a carbon tax on French energy sales. Macron has made climate change and lowering greenhouse gases a central component of both his domestic and foreign policies, only to face dramatic failure at the hands of his "yellow vest" countrymen. Macron's popularity has been low in France for months, and has now fallen to just a 23% approval rating. But the rioting across his country sends a frightening signal to...