America has long been prone to wild conspiracy theories - some dealing with the 1963 John F. Kennedy assassination or the Sept. 11, 2001, terrorist attacks. But the birther rumours have spread like wildfire in an age of 24-hour cable television news shows, Internet blogs and talk radio.
That has meant that at a time when the White House is pushing to overhaul the nation's health care system and fight high unemployment, it also has to contend with questions about whether Obama is a "natural-born" American, as the Constitution requires for anyone who would be president.
No serious investigation has produced doubt that Obama was born in the state of Hawaii. Even many of Obama's most virulent conservative critics dismiss the birther movement as a radical fringe that could damage the Republican Party.
But that hasn't stopped the birthers.
Joseph Farah, editor and chief executive at the conservative WorldNetDaily Web site, like many of those promoting questions about Obama's right to claim he is a "natural-born" American citizen, charge that the president's State of Hawaii "Certification of Live Birth" proves nothing.
"It's not true that Obama has released his birth certificate," Farah said in a telephone interview. He contends the president's Certification of Live Birth, a digital document that the state sends to any person needing a record of their birth there, omits the name of the hospital where Obama was born and the attending physician.
"It is very easy to get one of these certifications without proof of where a person was born," Farah said.
Farah's Web site carries advertisement for various conservative causes, including one that allows readers to donate to the organization's billboard campaign. The roadside advertisements read: "Where's the Birth Certificate?"
He and some others, who are fanning the birther movement, say they have never alleged Obama was born outside the United States. They just say he hasn't proved that he was born in the country.
Why? Conspiracy theories have a long history of thriving in the United States.
For example, some Americans still believe assassinated President John F. Kennedy was the victim mafia or Cuban or U.S. government cabal - not lone marksman Lee Harvey Oswald.
Absent evidence, still other Americans contend former President George W. Bush and his vice-president, Dick Cheney, were complicit in the terrorist attacks on Sept. 11, 2001.
Some say the birthers are promoting the conspiracy about Obama's foreign birth because they are racists, unable to accept the fact that an African American was elected president of the United States. Others see a link to attempts to convince voters that Obama was a Muslim, given that his Kenyan father was.
Not so, says Farah. He says those raising the questions about Obama just want to "see the truth of the situation."
On Oct. 31, 2008, Dr. Chiyome Fukino, director of the Hawaii Department of Health, said that state law prohibits release of "a certified birth certificate to persons who do not have a tangible interest in the vital record."
"Therefore I, as director of health for the state of Hawaii, along with the registrar of Vital Statistics who has statutory authority to oversee and maintain these type of vital records, have personally seen and verified that the Hawaii State Department of Health has Sen. Obama's original birth certificate on record in accordance with state policies and procedures."
Besieged by continuing question, Fukino issued another statement July 27:
"I ... have seen the original vital records maintained on file by the Hawaii State Department of Health verifying Barack Hussein Obama was born in Hawaii and is a natural-born American citizen."
Fukino has the support of her boss, Republican Gov. Linda Lingle, who was a supporter of Republican Sen. John McCain's candidacy in the 2008 presidential election.
Research has subsequently found that Obama's birth was announced in the columns of two Hawaiian newspapers printed in August 1961, notification taken from public records.
Brooks Jackson, director of FactCheck.org, has been deeply involved in investigating the birthers' claims, and says the "Certification of Live Birth" that Obama has produced is irrefutable proof that the president was born when and where he says he was.
And he said, "I have seen absolutely nothing that proves Obama was born anywhere but Hawaii."
He does fault Obama's media organization for posting a poor copy of the Certification of Live Birth on the candidate's Web site, giving ammunition to those who challenge his right to be president.
And continuing questions about Obama's birth place promoted a fairly emotional response late last month from White House press secretary Robert Gibbs.
"I almost hate to indulge in such an august setting as the White House briefing room, and I mean this seriously, discussing the made up, fictional, nonsense of whether or not the president was born in this country. A year and a half ago I asked that the birth certificate be put on the Internet because lord knows if you have a birth certificate and put it on the Internet, what else could be the story?"
"Nothing will assuage them," Gibbs said of the birthers.