As the Republican presidential nomination race went into the primaries season, Romney had not endorsed anyone but was one of the Republican establishment figures who were becoming increasingly concerned about the front-runner status of New York businessman Donald Trump. Romney publicly criticized Trump for not releasing his taxes, saying there might be a "bombshell" in them. Trump responded by calling Romney "one of the dumbest and worst candidates in the history of Republican politics". In a speech on March 3, 2016, at the Hinckley Institute of Politics, Romney made a scathing attack on Trump's personal behavior, business performance, and domestic and foreign policy stances. He said Trump was "a phony, a fraud ... He's playing members of the American public for suckers" and that "if we Republicans choose Donald Trump as our nominee, the prospects for a safe and prosperous future are greatly diminished". In response, Trump dismissed Romney as a "choke artist". Romney's speech represented an unprecedented attack by a major U.S. party's most recent presidential nominee against the party's current front-runner for the nomination.