Los Angeles -- There are many reasons that Irving David Rubin, who has been arrested some 40 times and has faced charges as serious as soliciting murder, has always emerged relatively unscathed.
Friends say Mr. Rubin, 56, the chairman of the Jewish Defense League, who was charged this week with conspiring to bomb a Los Angeles mosque and the office of a California congressman of Middle Eastern descent, has an extraordinary talent for testing the boundaries of what is legal without seriously breaching them.
Prosecutors have often said they simply lack the evidence to charge him, while his family attributes his legal fortunes to being on the side of righteousness. "And we have always had the best lawyers," said Shelley Rubin, his wife.
Mr. Rubin and Earl L. Krugel, 59, a league member, are being held without bond on the new charges.
Mr. Rubin's legal winning streak stretches nearly as long as his career with the league itself, which he joined in 1971 after attending what he found to be a rousing speech by Rabbi Meir Kahane, the group's leader.
"Don't sit down and have a cup of coffee with a Nazi," Mr. Rubin later recalled the rabbi's saying. "Don't try to be a nice guy. Smash him."
Within months, Mr. Rubin began staging protests against the treatment of Soviet Jews and squaring off with Nazis, sometimes violently, culminating in an arrest for the attempted murder of a Nazi he had brawled with in a Hollywood television studio. As was often the case throughout Mr. Rubin's three decades of militancy, the investigation was scrapped for lack of evidence. There have been fines for minor infractions, but he has never been convicted of a felony.
Mr. Rubin's budding celebrity grew into national notoriety in 1978, when he held up five $100 bills at a news conference against a Nazi march in Skokie, Ill., and offered them to anyone who maimed or killed a member of the Nazi party.
"And if they bring us the ears, we'll make it 1,000," he said, according to court records. "This is not said in jest, we are deadly serious."
After an intense legal battle lasting several years, he was acquitted, astounding even some of his supporters. Whatever law enforcement officials threw at him, nothing stuck.
"He had the uncanny ability to come right to the line, and he didn't cross it," said Roger J. Diamond, one of Mr. Rubin's lawyers for the last 18 years. "If he didn't come close, he wouldn't have been charged."
Mr. Rubin's path to politics is perhaps a proverbial one. While playing on the streets of Montreal, his hometown, another child called him a dirty Jew, sending the young Irv Rubin racing to his mother, in tears. Rather than coddle him, she ordered him back out to fight, instilling the confrontational spirit that has so characterized his activism, Mr. Rubin's wife said.
But while his parents were liberals and union supporters, Mr. Rubin, ever the contrarian, gravitated toward conservatism. Not long after the family emigrated to the San Fernando Valley in 1960, Mr. Rubin joined the Young Republicans at a community college and proudly served as a page at the 1964 Republican National Convention in San Francisco, where Barry Goldwater won the nomination.
Yet it was the defense league that truly engrossed him, so much so that he cut his honeymoon short in 1980 to look after his cohorts. By the time he took the group's helm in 1985, he boasted of being one of the world's best known Jewish activists, and reiterated unique slogans for defending the religion: "For every Jew, a .22" and "Keep Jews alive with a .45."
The strident rhetoric cooled a bit, especially after the Federal Bureau of Investigation began investigating the defense league for the 1985 murder of Alex Odeh, an Arab- American activist who died in a bomb blast that injured seven other people. Mr. Rubin denied responsibility but brazenly said that Mr. Odeh got what he deserved, a statement he has repeatedly said he came to regret because it alienated would-be supporters and further injured his credibility.
Casting off his street attire for three-piece suits, Mr. Rubin soon began courting Jewish leaders he once denounced and defending Arab businesses in Jewish neighborhoods.
"He attempted to become somewhat of a mainstream member of the community," said Rabbi Allen I. Freehling, senior rabbi at the University Synagogue in Brentwood, Calif. In prior years, Rabbi Freehling made sure the police were around anytime Mr. Rubin showed up. But as his stance softened, Mr. Rubin got to address the congregation, without having to heckle.
"In most instances, his transformation simply wasn't credited as being real," Rabbi Freehling said, "but I gave him credit for trying."
Still, violence continued to surround Mr. Rubin, and in 1992 he was arrested and accused of hiring a defense league sympathizer to kill a Los Angeles businessman in a dispute over money, not politics. Four days later, Mr. Rubin was released without being charged.
"The police informant was a complete flake," said Steven Goldberg, Mr. Rubin's lawyer. "The case went away so fast that there wasn't much for me to do."
The reliability of government informers has long been challenged by Mr. Rubin and his lawyers and is likely to become the central part of his defense against the current charges of conspiring to bomb the King Fahd mosque here, along with the office of Representative Darrell Issa, a Republican.
In 1984, Mr. Rubin sued the city of Los Angeles for planting an undercover officer in the ranks of the defense league. After befriending Mr. Rubin, the suit said, the officer urged the group to blow up the Rev. Jesse Jackson's presidential campaign office. The city refused to defend the suit on national security grounds, a highly unusual legal claim for a municipality, but succeeded in getting a state court to throw out the case.
A state appeals court reinstated the lawsuit in 1987, but the city gave Mr. Rubin an undisclosed amount of money to settle the case.
Now, Mr. Rubin's lawyers are arguing that the government's newest informer, a member of the defense league who has admitted committing crimes for the defense league in the past, is again trying to set him up with the help of law enforcement officials.
"You almost think of a vendetta," said Brian Altman, Mr. Rubin's lawyer in the current case.
The Los Angeles office of the F.B.I. defended the impartiality of its forces and rejected any suggestion of bias against Mr. Rubin.
For his part, Mr. Rubin makes no secret of his enmity for the spread of Islam, or for those who kill in its name. On the league Web site, a special message appeared until shortly after Mr. Rubin's arrest: "We pray to G-d Almighty to help us avenge the deaths of every single victim of Arab/Islamic terror."
"That was me," Mrs. Rubin said. "It was hyperbole."