HAMBURG, Germany, Jan. 24 - Horst Mahler, a former Marxist urban guerrilla and lawyer for the Red Army Faction, now represents the extreme right-wing National Democratic Party. But the virulence of his views has not diminished, and his outspoken comments on the Sept. 11 terrorist attacks in the United States have landed him back where he was decades ago - in court.
Last week, Mr. Mahler went on trial here on charges of approving of crimes and inciting violence, and could face three years in jail if convicted. A few weeks after the attacks in 2001, in a broadcast interview with Norddeutscher Rundfunk, the public network in North Germany, he called the terrorists' actions justified.
"It was frightening, but one also had the feeling that at last, finally, they had been hit in the heart," Mr. Mahler said then. "And it will certainly make them think. So, I say it was an action that, as cruel as it was, was justified."
In other comments in a letter posted on his Web site, Mr. Mahler has expressed more strident admiration for the Sept. 11 attacks.
"For decades, the jihad - the holy war - has been the agenda of the Islamic world against the Western value system. The Anglo-American and European employees of the global players, dispersed throughout the world are - as Osama bin Laden proclaimed a long while ago - military targets. Only a few need be liquidated in this manner; the survivors will run off like hares into their respective home countries, where they belong."
Mr. Mahler, 67, was sentenced to 10 years in prison in 1974 for bank robberies in connection with the Red Army Faction terrorist group. Once part of the extreme left that violently opposed residual Nazi tendencies in Germany, he is now known for anti-Semitic and anti-American rants.
In the opening day of his trial, Mr. Mahler confirmed the comments about the Sept. 11 attacks, but argued that the program's editing took them out of context. In a telephone interview, he explained, "I stand by what I said, but they cut out some of my other comments in which I said that this is not the way to fight back. The oppressed should win not with war, but with spiritual debate."
Prof. Hajo Funke, a political scientist at Berlin's Free University, studies right-wing extremism and was once a student with Mr. Mahler in the 1960's. He said the activist and his party are generally careful to stay within legal bounds when voicing their views, in part because the party faces a proposed government ban, which it is currently contesting in Germany's constitutional court.
"As a lawyer, he knows where the boundaries are and usually disguises his message," Mr. Funke said of Mr. Mahler.
By apparently justifying a violent act, Mr. Mahler may have infringed the law and weakened his party's case. Last year, Mr. Mahler was fined 7,200 euros in another German court for similar comments about the attacks.
German law limits free speech in cases of incitement and hate. The statutes were strengthened in the 1980's after complaints from Germany's Jewish community that post-war laws were too vague to prosecute neo-Nazis for propaganda, especially denials of the Holocaust. The Constitution also allows the banning of extremist political parties.
"These laws arose from the background of Germany's Nazi past and the persecution of the Jews," said Klaus Geppert, a law professor at the Free University. "Because of the German experience, we cannot accept anti-Semitic or racist expression."
According to Mr. Funke, Mr. Mahler's party has won followers by combining anti-Semitism and xenophobia with conspiracy theories about American power. Between 1996 and 2000, party membership grew from 3,500 to 6,500 members, particularly from unemployed youth in the eastern part of Germany.
"Mahler's vision is the most destructive of all of those expressed by German neo-Nazis," Mr. Funke said. "This is a confluence of Hitler's anti-Semitism and anti-imperialist nationalism."
In the Hamburg court last week, Mr. Mahler called the United States, "the bloodiest and most imperialist power the world has ever seen," according to the Associated Press.
He also said the Sept. 11 attacks were part of an American conspiracy. "It's not true that Al Qaeda had anything to do with it," he said.
The comments appeared to reflect an unsettling development in Mr. Mahler's ideology. In October, Mr. Mahler and his party's leader, Udo Voigt, reportedly attended an event at Berlin's Technical University sponsored by Hizb ut-Tahrir, an Islamic militant group with 27,000 members in Germany that was recently banned here for extremism and for spreading anti-Semitic propaganda in universities.
For Mr. Mahler, making common cause with Islamic groups has some precedent. He and other members of the Red Army Faction received terrorist training in Lebanon in the early 1970's from Al Fatah.
Mr. Mahler, who is defending his party in court against the government petition to ban it, is not the only former leftist in Germany to have made a political transformation. The German Interior Minister, Otto Schily, who instigated the government's petition, was also a Red Army Faction lawyer, and he once represented Mr. Mahler while he was a fugitive in the underground.