YOU DON’T SAY: Divisions within GOP over Trump’s candidacy are growing.

A campaign full of racial overtones and petty, R-rated put-downs grew even uglier Sunday after Trump declined repeatedly in a CNN interview to repudiate the endorsement of him by David Duke, a former grand wizard of the Ku Klux Klan. Trump had disavowed Duke at a news conference on Friday, but he stammered when asked about Duke on Sunday.

Marco Rubio, who has been savaging Trump as a “con man” for three days, responded by saying that Trump’s defiance made him “unelectable.” The senator from Florida said at a rally in Northern Virginia, “We cannot be the party that nominates someone who refuses to condemn white supremacists.”

The GOP race began as embarrassment of riches, and now it’s just an embarrassment.