Federal agents are arresting spouses of Americans, tech workers and others whose visas have expired, including many who have active applications to stay in the country. The Trump administration has begun arresting foreign citizens with expired U.S. visas as they travel through airports, including spouses of Americans, according to documents obtained by The New York Times and interviews with immigration lawyers — a tactic that opens up a vast new pool of people for deportation. Immigration agents in plain clothes have whisked away targets at check-in counters and arrival gates, with enforcement actions in at least 15 airports in recent...