WASHINGTON – For decades, immigrants who have followed the rules and have not broken the law have had hopes of earning a green card, a document that allows them to live legally in the United States and gain a path to citizenship.But under new guidance issued by the Trump administration, immigrants can now be denied a green card for expressing political opinions, such as participating in pro-Palestinian campus protests, posting criticism of Israel on social media and desecrating the American flag, according to internal Department of Homeland Security (DHS) training materials reviewed by The New York Times.The documents, which have...