For perhaps the first time in the campaign, the full spotlight is on Mike Pence, a man who likes to portray himself as an aw-shucks Midwesterner. PHOTOGRAPH BY TOM WILLIAMS / CQ ROLL CALL / GETTY

According to the Merriam-Webster online dictionary, this is the definition of the word "deplorable": "very bad in a way that causes shock, fear, or disgust : deserving to be deplored." If there is any public figure in America who fits that definition, it is surely David Duke. The Southern Poverty Law Center, which tracks extremist individuals and groups, describes Duke as "the most recognizable figure of the American radical right, a neo-Nazi, longtime Klan leader and now international spokesman for Holocaust denial."

For readers too young to remember Duke in his prime, it is perhaps worth recalling a few details from his résumé. According to a 1995 biography by Tyler Bridges, Duke sometimes wore a Nazi uniform at Louisiana State University when he was a student there, in the late sixties. In 1974, he founded the Knights of the Ku Klux Klan, which he claimed was a newer, more moderate and open version of the K.K.K. (It admitted women and Catholics.) In reality, according to the Southern Poverty Law Center, "Duke achieved a remarkable shift in Klan targeting—from blacks to Jews."

In the nineteen-eighties, when he tried to disassociate himself from the Klan and went into electoral politics, Duke’s obsession with Jews was a cause for concern for some of his advisers, who thought it limited his audience. The Financial Times's Gideon Rachman once recalled one of Duke's campaign managers telling him, "The Jews just aren't a big issue in Louisiana. We keep telling David, stick to attacking the blacks. There's no point in going after the Jews. You just piss them off, and nobody here cares about them anyway."

Duke wasn't to be put off. In 2004, he published a seven-hundred-page tract called "Jewish Supremacism: My Awakening to the Jewish Question," in which he cast doubt on the Holocaust and claimed that "organized Jewry has pursued a successful agenda that has amassed incredible power in modern times." On September 11, 2012, the eleventh anniversary of the 9/11 attacks, Duke wrote on his Web site, "Israel, Zionism, and Jewish Supremacist control of America are the primary causes of terrorism, instability and conflict in the world today. All other theories are merely diversions away from this ultimate truth." The following year, an Italian court expelled him from the country, where he had been living, saying that it considered him "socially dangerous for his racist and anti-Semitic views."

This is the man Mike Pence refused to call deplorable during an interview with CNN's Wolf Blitzer, on Monday. Blitzer had brought up Hillary Clinton's statement, last Friday (which she subsequently walked partially back), that half of Trump's supporters belong in a "basket of deplorables." Blitzer then mentioned Duke's name, suggesting that he and other white nationalists might rightly fit into that category. (Earlier this year, Duke endorsed Trump.) "Right?" Blitzer asked Pence.

"I'm not really sure why the media keeps dropping David Duke's name," Pence said. "Donald Trump has denounced David Duke repeatedly. We don't want his support, and we don't want the support of people who think like him." Blitzer then interjected, "Will you call him a deplorable?" To which Pence replied, "No, I am not in the name-calling business, Wolf. You know me better than that."

The matter didn’t end there. On Tuesday morning, at a press conference on Capitol Hill, Pence again refused to use the word "deplorable" to describe Duke. He reiterated that he and Trump had denounced Duke in the past and that they didn't want his support. Pence did describe Duke as a "bad man." But he said he wasn't going to "validate the language that Hillary Clinton used to describe the American people."

From a political perspective, Pence's refusal to change tack was somewhat puzzling. His interview with Blitzer had given the Clinton campaign an opportunity to turn the "basket of deplorables" story to its advantage. On Monday night, Clinton posted a message on Twitter that said, "If you won’t say the KKK is deplorable, you have no business running the country”—a view that is hard to argue with. In a television interview on Tuesday morning, even Kellyanne Conway, Trump's campaign manager, indicated that Pence should have called Duke deplorable—if only to avoid the headlines that his refusal to do so had produced. "He should—sure," Conway told CNN's "New Day."

Evidently, Pence received the same counsel from at least one other prominent Republican during a round of good-will meetings with G.O.P. members of Congress on Tuesday morning. Senator Mike Lee, of Utah, for one, had "emphasized that Republicans must identify David Duke’s racism as deplorable” during his meeting with Pence, a Lee spokesman told Ali Rogin, of ABC News. Why didn't Pence take the advice?

For perhaps the first time in the campaign, the full spotlight is on Pence, a man who likes to portray himself as an aw-shucks Midwesterner, and who among some Republicans is regarded as the acceptable face of the Trump campaign. It is possible that Pence was following his running mate's lead in his statements about Duke, even down to the use of the word "bad." At the end of February, Trump ran into a storm of criticism after he failed to disavow Duke during an interview with CNN's Jake Tapper. Rather than correcting this omission immediately, Trump blamed a bad earpiece and lashed out at the media. Finally, he said on MSNBC's "Morning Joe," "David Duke is a bad person, who I disavowed on numerous occasions over the years. . . . I disavowed him in the past. I disavow him now."

It is easy to imagine that the Trump campaign wants to keep the "basket of deplorables" story going, even if reporters and the Clinton campaign want to keep bringing up Duke. On Tuesday, Pence tried to turn Clinton's tweet on its sender, saying the original "deplorables" remark should disqualify her from the Presidency. "Anyone who has that low an opinion of the American people should not serve as President of the United States of America,” he said.

Pence didn't stop there. He also sought to downplay Duke's endorsement of Trump, saying he didn't think it was significant, “any more than the father of a terrorist who killed forty-nine Americans was seen at a Hillary Clinton rally, cheering her on.” As the Washington Post_ _reported, this was a reference to Seddique Mateen, the father of the Orlando killer Omar Mateen, who in early August appeared at a rally for Clinton, in Kissimmee, Florida. “We live in a free country, and people of ill motives have associated themselves with politics," Pence went on.

But these statements by Pence only raised more issues. It has been reported that Seddique Mateen, who was born in Afghanistan, made a series of videos commenting on the internal politics of his former country, and in one of them praised the Taliban for its activities in Waziristan. But in June, after his son killed forty-nine people at a gay night club in Orlando, Seddique Mateen publicly apologized to the American public, saying that he was "very angry and mad" at his son. He added, "I always [was] telling him that . . . the terrorists and terrorism are the enemy of the whole humanity." After attending the rally for Clinton, Seddique Mateen gave an interview to a local television station in which he said, "I wish my son joined the army and fought ISIS—that would have been much better." He went on, "I love the United States. I've been living here a long time."

Rather than dragging Seddique Mateen into a political argument he has nothing to do with, it would surely have been easier for Pence to say that Duke and the K.K.K. were deplorable, despicable—anything stronger than “bad”—and move on. But, for whatever reason, that is a step he is still refusing to take—which is itself deplorable.