WASHINGTON - Last summer, Barack Obama was fending off accusations he was a secret Muslim who hung around with terrorists.

A year later, he's facing accusations he wasn't born on American soil, possesses an inauthentic birth certificate and is therefore illegally serving as the 44th president of the United States.

It's largely the same group of conspiracy theorists involved in both sets of allegations - a small sect of Republican voters who maintain Obama has no right to be president despite overwhelming evidence to the contrary.

And it's all made for some entertaining political theatre in recent weeks as the mainstream media sat up and took notice of the allegations.

Until then, major publications and all-news networks had largely dismissed the "Birther" online movement as the blatherings of the mentally unhinged.

But the increasing Birther buzz this summer has prompted Democratic members of Congress, the White House and the state of Hawaii to push back.

The House of Representatives has unanimously approved a Democratic resolution celebrating the 50th anniversary of Hawaii's statehood. The resolution includes this line:

"Whereas the 44th President of the United States, Barack Obama, was born in Hawaii."

Republican Michele Bachmann initially opposed a vote on the resolution, but she ended up voting in favour.

White House press secretary Robert Gibbs dubbed the Birther accusations as "made-up, fictional nonsense" and bemoaned the fact that "for $15, you can get an Internet address and say whatever you want."

"The president was born in Honolulu, Hawaii, the 50th state of the greatest country on the face of the Earth," Gibbs forcefully told a White House press briefing.

Hawaiian officials, who had already verified Obama's birthplace before the presidential election in November, said again this week that they had checked and confirmed that Obama was born in Hawaii and is a natural-born U.S. citizen, a constitutional requirement of any president.

"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," said Dr. Chiyome Fukino, Hawaii's health director.

"I have nothing further to add to this statement or my original statement issued in October 2008 over eight months ago."

Birthers, however, point to the confidentiality of the original record as a sign that the president must be hiding something.

"Would you hire a babysitter to care for your children without completely checking them out, and making them prove to you that they are trustworthy and legitimate to do that job?" wrote a commenter named Sarah Marble on the Phoenix Business Journal website on Tuesday.

"Well, it makes logical sense that we would require the same from the person put in place to care for our nation."

The emotionally charged debate has resulted in some memorable - if mystifying - media moments.

Watergate mastermind G. Gordon Liddy was reduced to slumping and muttering in his chair last week as an aggressive Chris Matthews of MSNBC - which has positioned itself as the antidote to the right-wing Fox News - made mincemeat of his pro-Birther arguments.

CNN's Lou Dobbs had to be shut down by Joe Klein, the president of the cable news network, for continuing to insist on his talk show that the Birthers were onto something by asserting the president was born in Kenya.

Dobbs kept the story alive even after his replacement, Kitty Pilgrim, debunked the theories in his absence.

Dobbs is facing calls for his resignation this week from the Southern Poverty Law Center, a civil rights group that found a surprisingly sympathetic ally in Fox's Bill O'Reilly, who declared the Birther theories "bogus" despite his own network's role in promoting them.

Indeed, some of the conservative movement's most high-profile personalities have bailed on the Birthers, who have been making the allegations since Obama first secured the Democratic presidential nomination last summer.

Ann Coulter recently called the movement's members "cranks" and compared them to Ku Klux Klan participants.

Mike Huckabee, who ran for the Republican presidential nomination in 2008, has been dismissive of the Birthers, arguing if their theories held any water, Hillary Clinton's campaign team would have uncovered the truth.

Even Rush Limbaugh, the right's loudest voice, has been largely silent about the Birthers, while the conservative National Review Online published an editorial on Tuesday staunchly declaring that Obama is an American citizen.

"The myth that Barack Obama is ineligible to be president represents the hunt for a magic bullet that will make all the unpleasant complications of his election and presidency disappear," the editorial read.

"Like Bruce Springsteen, he has a lot of bad political ideas; but he was born in the U.S.A."