It’s still too soon to be sure, but a new national survey adds to a growing body of evidence that it will be difficult for anyone else in the Republican field to stop Donald Trump’s march to the party’s nomination. Seemingly immune to criticism of his calls for mass deportation of illegal immigrants, construction of a wall along the U.S.-Mexico border and heavy-handed tracking of Muslim Americans, Trump has taken his biggest lead yet over the rest of his Republican rivals, according to the latest CNN/ORC Poll.