President Trump’s surprise decision to rapidly withdraw all U.S. troops from Syria is meeting with intense criticism by foreign policy experts, who denounce it as strategically stupid, reckless for national security and a blow to America’s global credibility. But inside Syria, the consequences are even more serious. For one example, 50,000 Syrian civilian refugees living under the direct protection of the U.S. military are suddenly fearing for their lives. For three years, civilians living in the Rukban refugee camp in the southeastern Syrian desert have survived because of the protection of U.S. forces encamped 10 miles away on a base...