Ross Perot's charges of Republican dirty tricks follow a long-established pattern of espousing elaborate, unproved conspiracies often directed against himself.
On numerous occasions, most recently in the third presidential debate, Mr. Perot has described assassination conspiracies directed against him and his family by enemies as varied as the North Vietnamese, the Black Panthers and Texas drug dealers. Dallas law-enforcement officials interviewed by reporters have said they do not believe the plots to be true.
Over the years, Mr. Perot has shown a great appetite for conspiracy theories from both the far-left and the far-right wings of American politics, lending an open ear to theories that range from secret global cabals, to Byzantine tales of vast criminal enterprises undertaken with secret government approval, to talk of organized evil that stretches across continents and over decades, or even centuries.
Mr. Perot's son-in-law and general counsel, Clayton Mulford, acknowledged last month the Perot political organization had hired an investigations firm in California to run background checks on various campaign volunteers.
Mr. Perot's most flamboyant claim of conspiracies directed against himself came Oct. 19, in the third presidential debate, when Mr. Perot claimed that the Vietnamese had sent a team of Black Panther members to kill him in 1969, and that, later, agents of Texas drug dealers had tried to kill his family.
Regardless of what the law-enforcement officials believe, Mr. Perot has, by many accounts, for years been deeply concerned with what he believes to be plots to kill him and his family.
A former private security consultant who worked for Mr. Perot for several years, and who spoke on condition of anonymity, said Mr. Perot's north Dallas estate was protected with a security system worthy of a military installation, including a sophisticated system of cameras and movement sensors that fed information to private security officers keeping a 24-hour vigil in a command post on the property.
The security consultant also described Mr. Perot as obsessed with the sense of constant threat to himself and his family, to the point where he would sometimes prowl the grounds himself, armed with an automatic rifle.
In the debate, Mr. Perot said: "The Vietnamese had sent people into Canada to make arrangements to have me and my family killed. The most significant effort they had one night is five people coming across my front yard with rifles."
Mr. Perot told ABC News that he did not report the incident to the police and that his own security men had handled it. He credited a guard dog with chasing the assassins away. "He worked them like a sheep dog," Mr. Perot said.
But ABC World News Tonight, which investigated the story, found considerable reason to doubt it. "Listen to me," said Paul McCaghren, who headed Dallas police intelligence operations in "It didn't happen. It did not happen."
Mr. McCaghren explained: "Well, there were only about eight people here that belonged to the Black Panther Party. Two of those people worked for us and they told us every day what was happening."
No group could have tried such a serious assassination attempt on Mr. Perot without law enforcement officials hearing of it, he added. "If five members of the First Baptist Church with rifles had come onto his lawn, we would have found out about it."
Mr. Perot is no stranger to a number of people who have spent years in the murky, convoluted world of conspiracy theories.
Daniel Sheehan, head of a left-wing Washington-based group called the Christic Institute, has said that Mr. Perot was receptive to his theory that U.S. officials were involved in a fantastic intrigue of drugs and weapons sales in Southeast Asia and Central America.
Mr. Sheehan and several colleagues say Mr. Sheehan played a central role in convincing Mr. Perot in 1984 that Richard L. Armitage, a top Department of Defense official, was involved in a vast, shadowy drugs-and-guns smuggling scheme that Mr. Sheehan called the Enterprise.
The accusations against Mr. Armitage have been dismissed as false by a number of present and former government officials, and an FBI inquiry resulted in no criminal charges.
Mr. Sheehan brought a federal lawsuit based on his theory against Mr. Armitage, a number of Nicaraguan rebel leaders and various former officials of the armed forces and the CIA. The suit asserted that all these men were part of a group called the Secret Team, which conspired to form a gigantic criminal enterprise smuggling drugs and weapons, laundering money, and financing covert actions in Central America and the Middle East.
In 1988, U.S. District Court Judge James L. Kinf dismissed the suit as baseless, accused Mr. Sheehan of knowingly perpetuating a fraud and fined the Christic Institute $1 million, a verdict upheld by the Supreme Court.
But in 1986, the suit was still active, and on Oct. 21 of that year, Mr. Sheehan received a telephone call from a friendly Texas businessman.
The businessman, he recalled, said: "Hello, this is Ross Perot. I've heard that you've got all kinds of important information about some really bad actors. I've got wind of the same stuff and we need to talk about it."
A few months later, Mr. Perot arranged to meet Mr. Sheehan at the Naval Academy in Annapolis, Md., where Mr. Perot was giving a speech. Mr. Sheehan says that he and Mr. Perot talked for some time and that Perot then flew him in his private jet back to Texas.
All told, Mr. Sheehan remembers at least six occasions in which he and Mr. Perot discussed the matter. Mr. Perot also visited an associate of Mr. Sheehan's, a free-lance investigator, to pursue it further.
James Squires, Mr. Perot's former spokesman, has acknowledged the plane flight to Texas.
Mr. Sheehan said Mr. Perot had proposed taking the information about Mr. Armitage and other suspected participants in the conspiracy to then-vice president George Bush.
"I told him that was a bad idea, because it was pretty clear George Bush was part of the conspiracy, too," Mr. Sheehan said.
Instead, he said, he persuaded Mr. Perot to take the accusations to FBI Director William Webster, which Mr. Perot did. The resulting investigation found no evidence of criminal wrongdoing on the part of Mr. Armitage.
James "Bo" Gritz, a former Green Beret colonel and the author of a right-wing conspiracy theory that describes the world as controlled over several centuries by a cabal of international financiers, most of them Jewish, also claims to have met with the man he calls simply "Ross."
Colonel Gritz has described meeting Mr. Perot at least once and speaking to him on the telephone other times to elicit support for Mr. Gritz's failed attempts in the early 1980s to find and rescue U.S. servicemen in Southeast Asia.