The United States has 14,000 troops in Afghanistan, 39,000 in Japan, 34,805 in Germany, 23,000 in South Korea, and around 5,200 in Iraq. Our military protects the borders of countless nations. Except our own. In 1919, we had 18,500 soldiers on the border. “Twice a day every foot of the border line is patrolled by cavalrymen and infantrymen,” the New York Times noted. A hundred years later, President Trump’s proposal to use the military to secure the border is controversial even though Marines fighting drug cartels have come under fire from drug smugglers. El Salvadoran migration has inflicted 207 murderers...