Leaders of the Group of 20 agreed today to fix the world trading system after difficult, all-night talks in the Argentine capital, but only 19 of them agreed to support the Paris accord on fighting climate change with the United States the lone holdout. The official summit statement acknowledges flaws in global commerce and calls for reforming the World Trade Organization. It doesn't mention the word "protectionism," however, after negotiators said that had met resistance from the United Unite States.