Donald Trump has had better Sunday mornings. The Republican presidential front-runner stepped in controversy when he repeatedly declined to repudiate white supremacist support Sunday, passing up a chance to reject backing from former Ku Klux Klan leader David Duke. The GOP front-runner said he was unfamiliar with white supremacist groups, and said he would not specifically repudiate them before researching them.

At a press conference Friday, Trump did reject Duke’s endorsement, however, and Newt Gingrich later came to Trump’s defense on Twitter.