(CNN) - Donald Trump did not back down Tuesday from his questioning of President Barack Obama's birthplace, instead arguing heatedly with CNN's Wolf Blitzer that "a lot of people do not think it was an authentic certificate," though he declined to offer names of experts who agree with him.
The issue of Obama's birth - litigated in the 2008 presidential campaign, then settled when the Obama White House released the longform version of the certificate in April 2011 - is being brought to the fore in no small part by Trump, who is also set to fundraise alongside presumptive Republican presidential nominee Mitt Romney Tuesday evening.
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On CNN's "The Situation Room" Tuesday, Trump maintained that Obama's birthplace is a matter of opinion, rather than fact.
"Everybody's entitled to your opinion," he said. "You know my opinion and you know his opinion and that's fine. We're entitled - as he said yesterday in the airplane - we're all entitled to our opinions and he's entitled to have his opinion. I don't happen to share that opinion, it's wonderful."
Blitzer presented Trump with newspaper announcements of Obama's birth from 1961.
Trump interrupted, "Can you stop defending Obama?"
"Donald, you're beginning to sound a little ridiculous, I have to tell you," Blitzer replied.
"You are, Wolf," Trump fired back. "Let me tell you something, I think you sound ridiculous."
Trump then alleged that the practice of filing U.S. birth announcements for an overseas birth was commonplace, though he offered no evidence.
"Many people put those announcements in because they wanted to get the benefits of being so-called born in this country," Trump said. "Many people did it."
Obama's longform birth certificate showed he was born in Hawaii on August 4, 1961 and was acknowledged as authentic by state officials. Natural born American citizenship is one of the Constitutional requirements for the presidency.
"Is it the most important thing?" Trump asked in an interview earlier on Tuesday. "In a way it is. You're not allowed to be the president if you're not born in the country."
Trump finds himself at odds with GOP presidential candidate Mitt Romney, whose spokeswoman pointed out in an email statement that "Governor Romney has said repeatedly that he believes President Obama was born in the United States."
But Romney made no effort to distance himself from the comments, even when presented with the opportunity by reporters on Monday.
"You know, I don't agree with all the people who support me and my guess is they don't all agree with everything I believe in," Romney said when asked about the issue. "But I need to get 50.1% or more and I'm appreciative to have the help of a lot of good people."
Trump said he has not spoken about the birther issue with Romney
"I haven't talked to Mitt Romney about it," he said. "What I speak to Mitt Romney about is jobs. What I speak to Mitt Romney about is China, because he's got a great view on China and how they're taking our jobs and taking our product and manipulating their currency so it makes it almost impossible for our companies to compete."
Trump spoke by phone with Blitzer in the interview from Las Vegas, where he and Romney will fundraise with former GOP presidential candidate Newt Gingrich.
Obama's campaign released a web video on Tuesday that said the 2008 GOP nominee "John McCain stood up to the voices of extremism in his party… Why won't Mitt Romney do the same?" In the video, McCain is seen addressing a woman who called Obama an "Arab," saying, "He's a decent family man, citizen that I just happen to have disagreements with."
The president's deputy campaign manager suggested Romney's alliance with Trump in light of the tycoon's statements calls into question how he would serve as president.
"Mitt Romney's continued embrace of Donald Trump and refusal to condemn his disgraceful conspiracy theories demonstrates his complete lack of moral leadership," Stephanie Cutter said in a Tuesday afternoon statement. "If Mitt Romney lacks the backbone to stand up to a charlatan like Donald Trump because he's so concerned about lining his campaign's pockets, what does that say about the kind of President he would be?"
White House Press Secretary Jay Carney said Tuesday the White House was forced to address the issue last year, "but not because we chose to, but because it was such a ridiculous distraction from the important business that we should be doing here that the president is committed to doing and Congress should be doing to help the economy grow and help it create jobs."
"We can revisit that but I think the American people are pretty fed up with this kind of nonsense," he said.
As evidence of his claims, Trump pointed to a biographical note published in the 1990s by Obama's literary agent, which said Obama was born in Kenya.
The literary agent recently apologized for the mistake.
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Donald Trump is an absolute disgrace. He is a charlatan and embarrassing to the Republican party. What is more disgraceful is Romney's holding hands with him. Please get Trump off the stage and lets talk about something more serious. I, as a Republican, have absolutely no regard for Trump and getting less serious about Romney.
The crazier Trump gets, the worse it is for Romney, who doesn't have the courage to step away from him.
I can't believe this birther stuff is anything but racism, and I believe Romney won't speak out against it because he's counting on the racist vote to win the election. SICK.
"Hi, I'm Donald Tramp, and I'm Mittens' surrogate and proxy, here to say all the slimy crap that Mittens can't say but WANTS SAID."
Denial of the truth is not an opinion, it's a delusion. Look it up in DSM-IV, morons.
Truth does not need to be "trumpeted". It has quiet strength.
My god. Way to stand up for yourself Wolfy. Grow a pair for crying out loud.
Trump seems to have caught that thing Charlie Sheen had. Next he'll be "winning".
So why would a very young and very pregnant white girl from Kansas, who's going to college in Hawaii in 1961, voluntarily fly all the way to Kenya just so she can give birth to her baby, and then fly all the way back to Hawaii? TODAY it takes minimum 30 hrs and 2 or 3 stops to get from Hawaii to Nairobi. In 1961, on prop planes, how long would a trip like that take? TODAY it costs $2000 or so. In 1961, how much did it cost? Probably close to the equivalent of a years salary. These logical questions NEVER get asked. HOW did she pay for the trip? WHY would she make such an arduous journey?
Donald, I am not mad at you but I like to advise, see, if you have too much fat in brain–brain will not work, I love you so I am telling, give some money to Obama' campaign. All ok.
johnborg: I don't think this is subconscious. Obama is black so (at the very least) not representative of them. He must therefore not be legitimate. If his dad had been, say, from Philadelphia, then there would be talk of ties to gangs instead of questions about birth country.
Was going to stay at Trump Chicago , NOT. Canceled my reservations Donald Trump Your Fired!
Trump is a blowhard and a bully. That he is a Republican, supporting Mitt doesn't surprise me. That anyone listens to this man, aside from those who are afraid of him, is a mystery.
An American citizen can be born in any country, as long as their parent (only one is necessary) meets all the requirements of citizenship. Perhaps The Donald should read the law. As long as President Obama's mother was an American citizen in good standing, it doesn't matter where he was actually born. However, it would be pretty farcical to allege that the State of Hawaii created a fraudulent long-form birth certificate at the request of any run-of-the-mill millionaire. And don't you know that when the President was born, his mother thought "Oh, he'll be president; I'd better fake up a birth announcement." How silly!
I demand that Trump produce his birth certificate and six sworn witnesses. Otherwise I will continue to believe he was born in another universe.
Trump is a ripely's believe it or not. Clueless, stupid, and a waste of space and time.
Trump has dementia in the first degree. Totally out of it.
Trump is wasting his time ... all the racists and ignorant Southerners are already going to vote for Romney.
Trump, Trump for all that he's worth
Keeps calling for the President's certificate of birth
So overly portentous
This host of Apprentice
The craziest man on the face of the earth.
Romney needs to kick this nut case to the curb....fast! Trump is imploding his campaign.
Can Trump get any more stupid? Can Romney become any more of a wuss than he has already shown himself to be? Both of them are an embarrassment.
Kenyan ambassador admits in 2008 then canidate obama was born in Kenya.The interveiw was on a detroit radio station WRIF.Not to mention his grandmothers comments in Kenya of his birth just down the road.Seems they all have the story wrong all but obama that is.
I believe that fear, greed, and power bring out the true nature of a person – Trumps true nature is he is a racist.
Birth is not an issue anymore...now....where are his College Transcripts? What was his GPA...?
The GOP really thinks they're going to win the Whitehouse? The economy was driven over the cliff under the careful watch of the last GOP President, they have spent 4 years whining that they lost the Presidency and refusing to participate in the Democratic process, refused to work with the other side of the aisle, refused to do their job and provide the American people the service they deserve from their elected politicians, flat out admit that their sole puprose over the past 4 years has been to remove 1 guy from office, and they want my vote? Really? Why would i waste a vote on people who care more about getting their party back in power than trying to do something productive for the country? I can't even imagine voting for that party right now, they need a strong message from the voters that divisive politics is not the way forward. The way forward is cooperation, recognition that left and right are still American and the majority of us still fall in the center... They need to quit pandering to the extremes of their party and start listening to the majority of us that want them to do their dang jobs.
Trump is SO full of it. If he's been looking into this and has investigators on the case, as he said last year, he would have found out quite early on and with no doubt that the birth announcement was placed by the hospital, not by Obama's parents. That, my friend Trump, is a fact. So when Trump said to Blitzer, "Many people put those announcements in because they wanted to get the benefits of being so-called born in this country," as if that's the case with the Barack Obama birth announcement, he either is boldfacedly lying OR he hasn't done a lick of "investigating" Obama's birth.