Liberal bloggers have made their first arrest.

A Minnesota man trying to get mainstream exposure for his claims that he once enjoyed sex and cocaine with Barack Obama made a scheduled appearance at the National Press Club in Washington, D.C. Wednesday, and was promptly picked up by law enforcement on an out-of-state warrant.

Larry Sinclair, 46, was allowed to deliver his presentation to the smattering of reporters in attendance before deputy U.S. Marshals quietly led him away in handcuffs, Sinclair's lawyer confirmed Thursday. Already burdened with a long rap sheet, Sinclair was wanted on a criminal warrant in Delaware.

The arrest followed a failed campaign by Firedoglake, a leading liberal blog, to prevent Sinclair from airing his allegations at the prestigious Press Club.

But a couple blogging from Paris then began trying to arrange for his arrest at the appearance – a plan that seems to have succeeded.

"After a phone call to the Washington, D.C. Police, we have verified that Lawrence Wayne Sinclair has been arrested at the National Press Club just after his press conference ended," bloggers at the Mitch and Nan Show trumpeted Thursday.

Sinclair claims to have had sex and snorted drugs with Barack Obama in the back of a limousine in 1999 while Obama was a state legislator. The claims are unsubstantiated, and Sinclair first made them in a YouTube video released this January, which has garnered over 900,000 views – despite Sinclair's long history of criminal fraud, and his flunking of a polygraph on the supposed tryst.

When Sinclair announced his plans to air his claims at the National Press Club, Mitch and Nan, and one of their readers in Washington, D.C., began coordinating to tip off law enforcement authorities on Sinclair's whereabouts. Other bloggers had already discovered that he was wanted on at least one outstanding warrant.

The reader, named "Margot", contacted the D.C. police, but was told the cops wouldn't arrest Sinclair unless they got confirmation that he was at the press conference, and were provided with a detailed description. The morning of the event, Sinclair helpfully posted a picture of himself on his blog, and in a post warned Obama supporters not to try and crash his press conference.

The photo allowed Margot to phone the police with a description. Then she went down to the Press Club to see the results.

"They may not have stopped the press conference but the police did show up, and took him away," she wrote in to the Mitch and Nan Show blog later. "I was just at the NPC building and there was one only police car left by the time I got there."

The feds had to pull rank on Washington, D.C. police officers who also showed up to arrest Sinclair.

Sinclair appeared in D.C. superior court for his arraignment Thursday afternoon. The court clerk confirmed he'd been listed as a "fugitive from justice."

Sinclair's attorney Montgomery Sibley, whose license to practice law has been suspended in Florida and Washington, D.C., says that he has arranged for a lawyer to represent Sinclair in Delaware.