During appearances on network television Feb. 28, Republican presidential candidate Donald Trump repeatedly declined to refuse the endorsement of David Duke, a former grand wizard of the Ku Klux Klan. While Marco Rubio and Ted Cruz both took aim at Trump. (The Washington Post)

They weren’t hard questions to answer.

“Do you condemn David Duke? And the Ku Klux Klan?”

A simple “yes” would have worked. But on Sunday, Donald Trump swatted away the easy answers and instead feigned ignorance about the KKK and its most infamous grand wizard. The Republican front-runner’s failure to provide what should have been a simple answer has raised even more disturbing questions about the man who is on course to lock down the GOP’s nomination for president.

The first question is why would Trump pretend to be so ignorant of American history that he refused to pass judgment on the Ku Klux Klan before receiving additional information? What kind of facts could possibly mitigate a century of sins committed by a violent hate group whose racist crimes terrorized Americans and placed a shameful blot on this nation’s history?

Why would the same man who claims to have “the world’s greatest memory” say “I don’t know anything about David Duke” just two days after he condemned the former Klansman in a nationally televised press conference? And with that amazing memory, how could Donald Trump have forgotten that he himself refused to run for president as a Reform Party nominee in 2000 because “Klansman” David Duke was a member of that same party?

These are questions that have no good answers for a Republican Party on the verge of nominating a man who sounds more like a Dixiecrat from the 1950s than the kind of nominee the GOP needs four years after losing Hispanics by 44 percent, Asian Americans by 47 percent and black Americans by 87 percent.

Sunday’s distressing performance is just the latest in a string of incidents that suggest to critics that Donald Trump is using bigotry to fuel his controversial campaign. The most explicit of all examples was his December proposal to ban Muslims from entering the United States. Mika Brzezinski, my “Morning Joe” co-host, called that political promise “frightening” and our debate with Trump got so heated that I eventually hung up on the candidate during the interview.

But what Mika and I found offensive ended up attracting even more Republican primary voters to Donald Trump’s campaign. His approval ratings kept rising over the next two months, and in last week’s South Carolina primary, 75 percent of South Carolina’s GOP voters supported that same Muslim ban.

The day I hung up on Donald Trump, I asked on air, “Is this what Germany looked like in 1933?” Later, I warned Republicans that Trump’s rhetoric could lead to a brokered convention where “the party will kill itself.” But it looks like I overestimated primary voters in the early GOP contests. A brokered convention is now just the fantasy of Republican elites and Marco Rubio fans. The harsher reality is that the next GOP nominee will be a man who refused to condemn the Ku Klux Klan and one of its most infamous grand wizards when telling the ugly truth wouldn’t have cost him a single vote.

So is this how the party of Abraham Lincoln dies?