Federal immigration agents newly ordered to U.S. airports by President Donald Trump to help relieve security line congestion may guard exit lanes or check passenger IDs. Their enhanced role comes as a budget impasse has air travelers frustrated over hourslong waits and screeners angry about missed paychecks. Trump says he's acting because Democrats have failed to agree on a bill to fund the Department of Homeland Security, and that's led to a partial government shutdown. The Senate is convening a rare weekend session and is expected to advance the nomination of Markwayne Mullin, the Republican senator from Oklahoma who's in line to be Trump’s next homeland security secretary.