We heard it over and over on the campaign trail: Donald Trump’s promise of a crackdown on criminals and undocumented immigrants at a scale and breadth this country had never seen before. Immigration and Customs Enforcement, commonly known as ICE, has swept into American cities and is detaining more people than ever before. However, 71 percent of those held in immigrant detention by the end of September did not have criminal convictions, according to the Migration Policy Institute, a think tank focused on immigration. Many law-abiding immigrants who followed the rules in their applications for visas, green cards or asylum are being taken into ICE detention centers.