In recent years, the U.S. has not deported more than half a million immigrants with a formal removal order in a single fiscal year, according to the Transactional Records Access Clearinghouse. If President-elect Donald Trump follows through on his promise of deporting all “illegal” immigrants during his four-year term, the country could see a deportation operation of unprecedented scale. How exactly will the mass deportation be carried out? And what effect will it have on the U.S. economy?