Talk of a possible registry of Muslims began when Kansas Secretary of State Kris Kobach, a Trump adviser, said that the President-elect's transition team is considering reinstating a registry similar to one Kobach helped create in 2002 under the Bush administration, the National Security Entry-Exit Registration System (NSEERS). The registry required male visitors and immigrants over the age of 16 from a list of several countries, most of which were majority Muslim, to register and periodically check in with officials. NSEERS was criticized for targeting Muslims, and the U.S. government stopped using the program in 2011.
Though the registry floated by Kobach does not technically target Muslims, Trump has previously seemed willing to create a registry based on religion. A year ago, Trump said that he "would certainly implement" a database of Muslims in the U.S.
Criticism of the registry described by Kobach ballooned on Thursday when a Trump surrogate said that the Japanaese internment camps created by the U.S. government during World War II provides precedent for a registry of Muslims.