PASADENA, Calif. -- Leaders in the so-called "birther" movement argued their case over President Obama's U.S. citizenship before a federal appeals court Monday in Southern California, claiming the full birth certificate he released last week had been doctored.

But it was unclear how far their arguments would go, given the previous failed lawsuits on the issue and concern from the court about whether the latest claim was filed too late to be considered.

Obama's production of the vital record was aimed at quashing any lingering doubt among critics who contend he shouldn't have been elected because he couldn't prove he was a citizen -- a prerequisite for the nation's highest office.

But it has not deterred Orly Taitz, an attorney at the forefront of the birther movement. On Monday, Taitz told a three-judge panel of the 9th Circuit Court of Appeals that the long-form birth certificate released by Obama is "not a true and correct image."

"It's very inventive computer art," she said.

Taitz and attorney Gary Kreep, on behalf of more than 40 plaintiffs, are seeking to revive a lawsuit challenging Obama's citizenship that was dismissed by U.S. District Judge David Carter in late 2009. They asked the panel to remand the suit to Carter in Orange County.

Carter dismissed the case on the grounds that the federal court system was not the proper venue to challenge a president's election.

The appellate panel seemed to concur, wondering how the lawsuit could have merit, given it was filed after the election and Obama had already taken office.

"You did not file a claim at the time when the kind of relief you would be talking about might be plausible," Judge Raymond Fisher said. "It doesn't do anything for your candidates now."

It wasn't immediately known when the judges would rule.

Obama had released a standard short form of his birth certificate before he was elected in 2008. He produced his full birth certificate last week amid growing doubts about his birth in the U.S. A recent New York Times-CBS News poll found that 45 percent of adult Republicans said they believed he was born in another country or weren't sure.

In releasing the document, Obama said he hoped the nation could focus on more serious issues. Donald Trump, who has considered a presidential bid in 2012, took credit for forcing the president's hand.

Taitz said she believes the birth record was falsified.

After the hourlong hearing, she said the document's serial number was out of sequence, the typing wasn't aligned, and it was printed on green paper instead of white paper like other Hawaiian birth records of that era.

She added she wants to travel to Hawaii with a forensic expect to look at Obama's records.

Both Taitz and Kreep have been unable to convince courts around the nation their lawsuits have merit. Among their arguments -- Obama may have dual citizenship and the president's alleged use of multiple Social Security numbers.

Taitz was ordered by a federal judge in Georgia two years ago to pay a $20,000 fine, calling her lawsuit against the president frivolous and the litigation an attempt to misuse the court system to push a political agenda.

Taitz sued in Georgia federal court on behalf of Army Capt. Connie Rhodes, who sought to avoid deployment to Iraq by claiming Obama wasn't born in the U.S.

Other plaintiffs in the case include conservative activist Alan Keyes, libertarian vice presidential write-in candidate Gail Lightfoot and other members of the military.

Assistant U.S. Attorney David DeJute acknowledged the courts may be the proper venue had a lawsuit challenging a candidate's citizenship been filed before an election.

"I think a candidate can challenge the qualification of another candidate, assuming of course that candidate does so in a timely manner," DeJute said.

For the birther movement, the 9th Circuit appeal is a difficult platform in which to make its argument. Not only are plaintiffs arguing before one of the nation's more liberal courts, they face bad timing with the recent release of Obama's birth certificate and the announcement that terrorist Osama bin Laden was killed by U.S. forces, which gives Obama political strength.

Kreep said the case is unprecedented and shouldn't be taken lightly by Obama or the courts.

"We have a man who, whether it's true or not, arguably is not a citizen or at least a naturally born citizen of the United States and is not eligible to serve," Kreep said. "The only recourse for the people is the courts."