Imagine what would happen if the Obama administration just deported the worst of the worst, the illegal aliens with criminal pasts linked to drugs, theft and sexual assault. According to The Heritage Foundation’s Hans von Spakovsky, crime would be reduced and the nation’s prison population would decline. Part of the reason why more criminal aliens are not deported is the policy of sanctuary cities. That policy has allowed 8,300 aliens to stay who were otherwise deportable, just in an eight-month period in 2014. And a good majority of them were not families looking for a better life in the U.S. but somehow failed to get their paperwork sorted out. According to the Center for Immigration Studies, 62% had previous criminal records and 1,900 were later arrested again for committing another crime. At the beginning of July, one such alien, sheltered from his sixth deportation by San Francisco’s sanctuary city policy, killed Kate Steinle. As von Spakovsky writes: “How many Americans have to be assaulted, injured, raped or killed, or have their homes, cars and personal property burglarized, stolen or damaged before both the federal government and local governments like San Francisco will finally do what is necessary to lock up criminal aliens who are a danger to the safety and lives of the public?” Municipalities are first and foremost supposed to ensure the peace, something that a sanctuary city policy erodes.