Republican presidential front-runner Donald Trump abruptly announced here Tuesday that he would not participate in Thursday’s scheduled debate, escalating his off-and-on feud with Fox News Channel and throwing the GOP campaign into turmoil.<br />Trump’s assertion, which his campaign manager insisted was irreversible, came less than one week before the kickoff Iowa caucuses.<br />He once again defied the conventional rules of politics, and used his power and prominence to shape the campaign agenda and conversation.<br />So far, Trump’s untraditional moves have only expanded his support, but his threatened boycott leaves him open to criticism that for all his tough talk he is ducking face-to-face confrontations with his opponents and scrutiny from the Fox moderators.<br />Given Trump’s past flirtations with boycotting Fox, many will doubt his declaration until they see the other candidates take the debate stage on Thursday night without him.
