With President-elect Donald Trump widely expected to turn back many of President Obama's progressive executive actions and legislation, a shadow from the past has reappeared that may also impact Obama's legacy: his birth certificate.

WND has learned that a news conference has been scheduled for Dec. 15 to make public the final conclusions of the investigation by the Cold Case Posse in Arizona's Maricopa County under Sheriff Joe Arpaio, who was defeated Nov. 8 in his bid for a seventh term.

Arpaio launched his Cold Case Posse, under the leadership of investigator Mike Zullo, in August 2011 at the height of the controversy over Obama's birth certificate. Dozens of lawsuits had been filed challenging Obama's constitutional eligibility to be president, alleging he wasn't a "natural born citizen."

The review was sparked by requests to the sheriff from his constituents, who feared a fraud had been perpetrated on the American people.

After Trump publicly raised the issue, Obama held a news conference in the White House and showed reporters what he claimed was his official Hawaiian birth certificate.

It is that document, not necessarily Obama's eligibility, that has been the focus of Arpaio's investigation.

On Wednesday, the PPSIMMONS blog, affiliated with author, pastor and radio host Carl Gallups, reported Arpaio had been planning to announce the news conference on a Phoenix television station, but the interview was postponed.

Gallups confirmed, however, that a press conference regarding the birth certificate has been scheduled for Dec. 15 at 4 p.m. Mountain Time.

Gallups, who is close to Zullo and the investigative team, told WND "this has been a long and arduous process for all who have been deeply involved in this case."

"The political and mainstream media interjections, accusations, and mischaracterizations of the investigation and the investigators have been relentless," he said.

"But there was too much information still coming in concerning this case for them to completely drop the investigation. So, according to the promise that Sheriff Joe Arpaio and Mike Zullo made, they continued on and dug even deeper."

Gallups said the press conference "will represent a conclusion of the matter concerning the validity of the represented birth certificate document that was put forth by the Obama administration and posted on the White House website."

'Preposterous notion'

WND reported in 2015 when the issue was raised once again in a CNN interview in which anchor Jake Tapper excoriated Arpaio for questioning Obama's document.

See the interview:

On CNN's "The Lead," Tapper said, "You've trafficked in this rather preposterous notion that Obama was not born in the United States and that he may have forged his birth certificate that he released."

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He continued, "Why would you risk your credibility on issues you care about – like illegal immigration, like law enforcement – by getting involved in this nonsense?"

"What do you mean 'risk'?" Arpaio asked. "I'm the chief law enforcement officer elected by the people. I have a right to investigate and speak out. I'm not talking about where he came from. I don't care where he came from. We're working on a fraudulent, forged government document. That's what we are doing."

Tapper interjected, "You're maintaining that the birth certificate that the president of the United States revealed and released to the public, you're maintaining that that is fraudulent?"

"That's right," Arpaio responded.

The CNN host asked, "Is there anyone, any credible law enforcement person outside of you and your organization and your contractors, who has any agreement with you on this?"

"No, they haven't looked at it," Arpaio said. "What, are you kidding? I'm probably the only law enforcement official who has looked into it. Nobody looks into it. They shy away from it."

Once again, a flustered Tapper interrupted: "Because the president was born in Hawaii."

"I don't care where he was born," Arpaio replied. "I'm talking about a fraudulent government document, a birth certificate. That's all I'm concerned with. That's a violation of the law."

Previously, Arpaio affirmed he was "pretty well convinced" Obama's birth certificate, as released by the White House in 2011, is a "fraudulent, fake document."

"I've been in law enforcement 55 years," Arpaio told "Aaron Klein Investigative Radio." "I think I know a fraudulent, fake document. I'm not a computer expert. I rely on my people. But I'm pretty well convinced it's a fake document."

Listen to "Aaron Klein Radio" clip of Joe Arpaio discussing Obama's birth certificate:

But Zullo has indicated the White House computer image of Obama's birth certificate contains anomalies that are unexplainable unless the document had been fabricated piecemeal by human intervention, rather than being copied from a genuine paper document.

See some of Zullo's evidence:

Zullo has noted that Reed Hayes, a document examiner who has served as expert witness for Seattle law firm Perkins Coie – the firm that flew an attorney to Honolulu to personally deliver two paper copies of the birth certificate to the White House – has concluded in a signed affidavit that the document posted on the White House website is "entirely fabricated."

The issue was complicated by Hawaiian officials refusing to verify any information about Obama's birth certificate. Even the hospital where Obama said he was born refused to cooperate.

Also, at the time Obama was born, only a short time after Hawaii was admitted as a state, there were a number of ways a Hawaiian birth certificate could have been obtained without the person having been born in Hawaii.

Republican 'cowardice'

In 2014, WND Columnist Christopher Monckton urged Republicans in the U.S. Senate to do their own investigation.

"One of the many dismal failures of the GOP since 2008 has been its failure to get to grips with the birth certificate issue," he wrote.

"The reason for the Republicans' cowardice was very clearly spelled out to me by a senior and experienced GOP congressman over dinner at my club in Washington, D.C., a couple of years ago. 'We all know the birth certificate is bogus,' he said, 'but we also know that anyone who dares to raise the issue will have his or her reputation trashed by the communist left.'"

He continued, "In my assessment, it is only when the GOP commands both the Senate and the House that it may find what in English we should call the cojones to do something about the birth certificate.

"When I first visited Sheriff Joe some years ago, it was at once apparent that he had more than enough credible evidence to go before a Federal District Court and demand orders of the court obliging the extremely reluctant 'Democrat' administration in Hawaii to hand over for forensic examination not only the original 'birth certificate' but also the relevant birth records of the Kapi'olani hospital. The attorney general of Arizona, in failing to permit the sheriff to apply for the necessary orders, is guilty of the grossest negligence."

He added: "When Mike Zullo, the sheriff's chief investigator, visited Hawaii with a colleague and contacted the police there in the normal way to report that they were carrying out an investigation, and then went to the Hawaii Health Department to try to interview certain officials, the department, instead of agreeing to assist the criminal investigation, called the police to have the sheriff's investigators removed from the premises."

Americans skeptical

At that time, six years into Obama's administration, WND reported a poll revealed nearly one-quarter of American adults didn't even believe he's a U.S. citizen, let alone a "natural-born citizen," and another 17 percent were unsure.

Rasmussen Reports found 41 percent of Republicans believed Obama is not an American citizen, a belief shared by 21 percent of those who are unaffiliated and 11 percent of Democrats.

"Just over 20 percent of Republicans and unaffiliated adults also are not sure, but only 7 percent of those in the president's party share that doubt," the polling organization said in a report titled "Have We Got A Conspiracy for You – 9/11? JFK? Obama's Citizenship?"

Overall, 23 percent said the theory that Obama is not an American citizen is true, and another 17 percent said they weren't sure. Sixty percent reject the theory as false.

The Constitution requires the president to be a "natural-born citizen" but does not define the term. Scholarly works cited by the Founders defined it as a citizen at birth by virtue of being born in the country to two citizens of the country, or merely the offspring of two citizens of the country. The birth certificate Obama displayed on the White House website declares he was born in Hawaii to an American mother and a Kenyan father.

Trump: 'I have no idea'

Trump, at the height of the controversy in 2011, said he couldn't be certain of the truth because so much has been hidden from the public.

At one point, he offered $5 million to the charity or charities of Obama's choice if he would release his passport records and authorize the colleges he attended to release his applications and other records.

Trump argued that those documents would show whether or not Obama ever accepted scholarship or other aid as a foreign student, which could preclude him from being a "natural-born citizen."

In an interview, ABC's Jonathan Karl charged Trump took on the "not serious" issue of eligibility.

"Why does that make me not serious?" Trump demanded. "I think that resonated with a lot of people."

Karl replied: "You don't still question he was[n't] born in the United States, do you?"

"I have no idea," Trump said. "I don't know. Was there a birth certificate? You tell me. You know some people say that was not his birth certificate. I'm saying I don't know. Nobody knows, and you don't know either. Jonathan you're a smart guy, and you don't know."

When Karl admitted he was "pretty sure," Trump jumped on the statement.

"You just said you're pretty sure … you have to be 100 percent sure," he said. "Jonathan, you said you're pretty convinced, so let's just see what happens over time."

Among the many records the Obama camp has refused to release are the marriage license of his father (Barack Sr.) and mother (Stanley Ann Dunham), name-change records (Barry Soetero to Barack Hussein Obama), adoption records, records of his and his mother's repatriation as U.S. citizens from Indonesia, baptism records, Noelani Elementary School (Hawaii) records, Punahou School financial aid or school records, Occidental College financial aid records, Harvard Law School records, Columbia senior thesis, Columbia College records, record with Illinois State Bar Association, files from his terms as an Illinois state senator, his law client list, medical records and passport records.

Go to the WND Superstore right away for all of Carl Gallup's books, "Be Thou Prepared," "The Magic Man in the Sky," "The Rabbi Who Found Messiah," "Final Warning" and the newest "When the Lion Roars."