CLEVELAND, Ohio -- A civil rights organization says in a new report that the National Alliance, once one of the nation's most powerful white supremacist groups, has virtually collapsed under the decade-long leadership of North Royalton resident Erich Gliebe.

The report, posted online today by the Southern Poverty Law Center, says the National Alliance has "become the joke of the neo-Nazi movement." The law center, a Montgomery, Ala., organization that monitors hate groups, says alliance membership has fallen from 1,400 a decade ago to about 75 -- "a tiny band of small-time propagandists, criminal thugs and attention-seeking losers."

Gliebe, 49, took over the National Alliance after leader William Pierce, author of the 1978 race-war novel "The Turner Diaries", died in 2002. Pierce, a former physics professor, led the alliance since the early 1970's and had a large following in the United States and Europe.

Since his death, the group has been splintered by internal revolts and failed leadership, said Mark Potok, editor in chief of Southern Poverty Law Center publications, who wrote the report.

"Gliebe's extremely poor leadership and lack of charisma have dramatically led to the decline of the National Alliance," Potok said in an interview.

Gliebe did not respond to requests for comment. A person who answered his cell phone Friday said he was Gliebe's friend and he would take a message. "I don't think he'd be interested in talking to The Plain Dealer," the man said.

Gliebe is a former pro boxer and 1981 graduate of Normandy High School in Parma, according to earlier Plain Dealer stories. He's been described by a Seattle publication as a suit-and-tie-wearing neo-Nazi.

The Southern Poverty Law Center once ranked him as a rising star of the "radical right." Gliebe had been a spokesman for the alliance and distributor of white power music through Resistance Records, the group's label.

Gliebe had formed the Cleveland chapter of the alliance, which is headquartered near Hillsboro, W. Va. Cleveland became the group's biggest and most important chapter, according to Potok. But the Cleveland unit now "reflects the general disarray into which the group has fallen," the report says. "What was once a monthly meeting held in a large restaurant meeting room attended by dozens of members has diminished to half a dozen members, at most" who meet at a West Side restaurant.

The report says Gliebe works as a part-time custodian at a local company. It contains scathing details of his divorce, describing his wife as a former stripper who in 2009 accused him of "deviant sexual behavior" involving Catholic schoolgirl uniforms.

The report also links the alliance to a number of violent crimes over the past 10 years, including a 2011 attempt to detonate a bomb laced with rat poison along the route of Martin Luther King Jr. Day marchers in Spokane, Wash. Kevin Harpham, who was sentenced to prison for the crime, had ties to white supremacist groups. The Southern Poverty Law Center said he had been a member of the alliance, but Gliebe at the time denied Harpham was a member.

Though leadership voids have caused the alliance and some other dominant hate groups of yesteryear to splinter, Potok said, the threat from extremists remains high. The number of radical hate groups, in fact, has been on the rise the past 11 years, the law center said in a March report.

"As a general rule, these groups often grown more dangerous when they are led poorly or not led at all," Potok said. "When you have strong leaders, it tends to keep the criminal violence in check."