Donald Trump spent a lot of time raising doubts over President Obama's birth certificate in 2011 – now his campaign says he believes Obama was born in the U.S., but Trump himself still hasn't clarified what he really thinks. (Peter Stevenson/The Washington Post)

Republican presidential nominee Donald Trump said in an interview here that he remains unwilling to say that President Obama was born in the United States, that he is more bullish than ever on his chances to win and that he is not exploring the launch of a new media company in case he loses the race.

Trump also made a far-from-subtle push — in the interview and in a letter from his doctor released Thursday — to be seen as vigorous and healthy, as his Democratic rival, Hillary Clinton, returned to the campaign trail after being treated for mild pneumonia.

In the interview, conducted late Wednesday aboard his private plane as it idled on the tarmac here, Trump suggested he is not eager to change his pitch or his positions even as he works to reach out to minority voters, many of whom are deeply offended by his long-refuted suggestion that Obama is not a U.S. citizen. Trump refused to say whether he believes Obama was born in Hawaii.

“I’ll answer that question at the right time,” Trump said. “I just don’t want to answer it yet.”

When asked whether his campaign manager, Kellyanne Conway, was accurate when she said recently that he now believes Obama was born in this country, Trump responded: “It’s okay. She’s allowed to speak what she thinks. I want to focus on jobs. I want to focus on other things.”

He added: “I don’t talk about it anymore. The reason I don’t is because then everyone is going to be talking about it as opposed to jobs, the military, the vets, security.”

Late Thursday, campaign spokesman Jason Miller said in a statement that Trump no longer doubted Obama’s birth in Hawaii and had done “a great service to the President and the country” by prompting Obama to release his long-form birth certificate in 2011. But Miller also repeated the widely debunked claim that Clinton and her campaign had questioned Obama’s birthplace in 2008, which is false.

Miller is among three Trump associates who have recently claimed a change of heart, but the candidate has yet to say so himself. Trump has repeatedly raised questions about Obama’s heritage over the past five years.

In the interview, Trump defended his wife’s immigration history; attacked targets including CNN host Anderson Cooper and Senate Minority Leader Harry M. Reid (D-Nev.); and said he had been “respectful” since Clinton fell ill but “that doesn’t mean that I’m going to stay there.”

Sitting in his plush, cream-and-gold cabin as his top aides looked on, Trump began by repeatedly recounting his poll numbers, which have ticked up nationally and in some key states.

Trump said a possible turning point in the race came last week when Clinton said that “half” of his supporters belonged in a “basket of deplorables” — a remark she has since said she regrets.

Speaking in Asheville, N.C., Sept. 12, Republican presidential nominee Donald Trump said his Democratic opponent Hillary Clinton “talks about people like they are objects, not human beings,” following her comments on Trump’s supporters. (The Washington Post)

“It’s the single biggest mistake in this political cycle, a massive comment, bigger than 47 percent,” Trump said, a reference to Mitt Romney’s controversial 2012 statement at a fundraiser about voters who receive government benefits or pay little in taxes. “When I first heard it, I couldn’t believe that she said it.”

Clinton and her campaign argue that some Trump backers are racist and misogynistic and have sought to link him to the “alt-right” movement of self-avowed white nationalists, many of whom have rallied around his candidacy.

“The alt-right. You know they came up with the term ‘alt-right,’ ” Trump said, blaming Clinton and her allies, although the term has been used within the movement for years. “I think the term itself is ridiculous. The alt-right. When did it come into existence? It was just made up.”

Trump was a leading and vocal proponent of the debunked conspiracy theory that the nation’s first black president was born overseas and thus not eligible for the White House. Obama released his Hawaiian birth certificate in 2011, but Trump has never disavowed his earlier claims.

The Republican nominee said he still believes he can win significant support from black voters. “I’ve come up with African American voters like a rocket ship,” he said.

When told again that the birther issue could still hang over his candidacy and its appeal to that voting bloc in particular, Trump glared and said, “I think it hangs over the reporters.”

There have been rumors and scattered media reports for months that Trump has been considering founding a media company with his friend Roger Ailes, former Fox News chairman, should he lose the presidency. But Trump said he has never had a conversation about launching a venture with Ailes or other prominent right-wing media figures.

“No, never did,” he said. “I want to win the presidency, and I want to make America great again. It’s very simple. I have no interest in a media company. False rumor.”

Trump characterized Ailes, who resigned from Fox News after a series of sexual-harassment allegations, as a trusted friend more than a formal adviser. “He’s certainly been very successful at what he does and on occasion, we’ll talk,” Trump said. “I love the benefit of his experience and knowledge. He’s had an amazing experience. But there is no role.”

Trump said Ailes has told him “some interesting things about past debates” during conversations they’ve had over several weekends at Trump’s golf club in Bedminster, N.J.

“Debate skills are either something you either have or don’t have. You have to prep. You have to have knowledge,” he said. “But when people say you have to be nice or not nice, well, I won’t really know until it begins. Because if she treats me with respect, I’ll treat her with respect. If she doesn’t, I’ll reciprocate. If she’s respectful of me, I’ll be that way with her.”

Trump said he was unconcerned that moderators may decide to fact-check during the forums.

“I don’t care. My facts are good. My facts are good. I don’t get enough credit for having my facts right,” Trump said. “They’ll say I’m wrong even when I’m right.”

Trump took an unprompted shot at Cooper, who is one of the moderators selected by the nonpartisan Commission on Presidential Debates. Trump said he would take part in the debate moderated by Cooper but remains unhappy with his selection.

“I don’t think Anderson Cooper should be a moderator, because Anderson Cooper works for CNN and over the last couple of days, I’ve seen how Anderson Cooper behaves,” Trump said. “He’ll be very biased, very biased. I don’t think he should be a moderator. I’ll participate, but I don’t think he should be a moderator. CNN is the Clinton News Network and Anderson Cooper, I don’t think he can be fair.”

On Wednesday, Trump’s wife, Melania, released a letter from her attorney, who attested with “100% certainty” that she had immigrated legally from Slovenia, following several news stories scrutinizing how she entered and worked in the United States before gaining citizenship.

With the letter, Trump said, there is no longer a need for his wife to hold a news conference on the topic, as the campaign once promised. He also reiterated his refusal to release his tax returns, as Clinton and all other presidential candidates have done for decades, citing an Internal Revenue Service audit that he says is ongoing.

Briefly discussing foreign affairs, Trump bristled at the idea that he had “embraced” Russian President Vladimir Putin with positive comments about him, including his contention last week that Putin was superior to Obama in leadership skills.

“By the way, that’s a totally false narrative. I haven’t embraced them. You know that,” he said. When told that he has been more warm to Putin than many other Republicans, Trump said: “No. No.”

“I simply said that Putin is a stronger leader than Obama,” he said.

Trump on Thursday released a letter from his longtime doctor, Harold N. Bornstein at Lenox Hill Hospital in New York, that summarized the candidate’s latest physical and discussed it on “The Dr. Oz Show.” It said he takes a statin drug to lower his cholesterol and has a body mass index in the overweight range but is in “excellent” condition.

Trump defended Bornstein — who has come under scrutiny after acknowledging that he rushed writing a previous hyperbolic statement on Trump’s health — as “very, very professional.”

“He’s never been exposed to the public like this, so he was having a little bit of a hard time,” Trump said.

Trump said Bornstein’s letter will be the final document that he will release on his health before the election. He does not plan to share a trove of medical files as other presidential candidates, such as Sen. John McCain (R-Ariz.), have done during previous campaigns.

“There is nothing else to release,” Trump said.

He took a swipe at Clinton, whose campaign on Wednesday released a two-page letter from her doctor that said she had been treated for “mild” bacterial pneumonia but is in overall good health and “fit to serve as president.”

“She didn’t give this. She didn’t give all of these EKGs,” Trump said, referring to an electrocardiogram test result included in the letter. “I took EKGs. She said her cholesterol is okay, I say what my cholesterol is. I give the good, the bad and the other cholesterols. I give all three cholesterols.”

When asked directly whether he has ever had a major illness or a heart attack, Trump said he has not. “No,” he said. “I’ve never had a scare.”

Trump shrugged off a question about whether he could use more exercise.

“I guess. But that’s exercise,” he said of his raucous rally speeches. “When you’re up there soaking wet, the room is 90 degrees because there are so many people. . . . It’s warm. It’s like that in a lot of rooms.”

Told that Reid had said that Trump is “not slim and trim,” Trump grimaced and waved his hand dismissively.

“Harry Reid? I think he should go back and start working out again with his rubber work-out pieces,” an apparent reference to the exercise band that snapped last year and caused Reid to fall and break a number of ribs and some facial bones.

Since Clinton fell ill Sunday at a memorial service marking the 15th anniversary of the 9/11 terrorist attacks, Trump has been mixed in his responses. He has sounded taunting in some of his recent remarks, such as when he wondered aloud at his rally Wednesday whether Clinton “would be able to stand up here for an hour and do this.”

“I don’t think so,” Trump told the cheering crowd.

“I asked a question,” Trump said in the interview soon after. “Everyone screamed ‘No!’ I want to be respectful. I’m a respectful person. That doesn’t mean that I’m going to stay there. But right now, she’s in bed recuperating and I want to be respectful.”

Trump also said that he resisted weighing in on Clinton’s illness Sunday on Twitter because “I thought it would be inappropriate to tweet when I saw her in serious danger.”

But was he tempted?

“No,” Trump said quickly. “No. I was not tempted. Not even a little bit.”