Washington (CNN) In a rollicking election season, one theme has endured: gaffes that would seriously damage any other politician leave Donald Trump unscathed. That could be changing. Trump is facing the toughest test of his campaign after a week in which he veered into a series of unexpected controversies and -- for a change -- seemed to struggle in his response. His parade of missteps on issues ranging from national security to abortion have left the Republican front-runner wading through his roughest patch yet on the campaign trail. Trump will learn whether he dealt his campaign serious damage on Tuesday when GOP voters in Wisconsin go to the polls. Some surveys show Texas Sen. Ted Cruz leading in the primary there and a loss for Trump would make it that much harder to secure the 1,237 delegates he'll need to secure the nomination before the GOP convention.Trump is facing toughest challenge of his campaignHe'll be tested during Tuesday's Wisconsin primary
During the same town hall, Trump abandoned his earlier pledge to support the eventual _ nominee if it wasn't him.