For over a century, Haiti has seen four large-scale foreign interventions that tried to quell violence in the fragile Caribbean nation. On Tuesday, the latest attempt saw its first measure of success. Two months after their arrival, foreign troops working with Haitian forces took back a gang-infested part of the capital, Port-au-Prince. The operation did not garner much attention perhaps because of 109 years of past failures by outside countries to restore order. “We must be patient,” a newly...