CINCINNATI — Thirty years after federal officials first sought to revoke John Demjanjuk’s citizenship, a lawyer for the former autoworker accused of being a Nazi death camp guard argued yesterday that a deportation order against his client should be thrown out.

The family of the 87-year-old man, who at one point had been extradited to Israel and sentenced to death, said they are shielding him from a legal battle that could end with his deportation to Europe. “He is, in a way, oblivious to what’s going on in the courtroom, and we kind of make it that way so he doesn’t sit there and worry about this,” Ed Nishnic, John Demjanjuk’s former son-in-law, said yesterday.

The 6th U.S. Circuit Court of Appeals heard arguments on Mr. Demjanjuk’s challenge to a final removal, or deportation, order issued in 2005. His attorney, John Broadley, told the panel that the nation’s chief immigration judge lacked the authority to issue the order.

“The chief immigration judge is purely an administrative official,” Mr. Demjanjuk’s attorney, John Broadley, told the panel. “The attorney general did not specify that the chief immigration judge was entitled to hear removal cases.”

That argument is absurd, a Justice Department lawyer, Robert Thomson, told the court.

“In plain language, the title chief immigration judge means he’s a judge,” Mr. Thomson said. “Why would that be the title if he wasn’t to be a judge?”

The government initially claimed Mr. Demjanjuk was the notoriously sadistic guard at the Treblinka camp known as “Ivan the Terrible.” Officials later concluded that he was not, but a judge ruled in 2002 that documents from World War II prove Mr. Demjanjuk was a Nazi guard at various death or forced labor camps.

Mr. Demjanjuk, who lives in the Cleveland suburb of Seven Hills, has steadfastly maintained that he was a Nazi prisoner himself, forced to work as a guard, and that he hurt no one. His son, John Demjanjuk Jr., watched yesterday’s arguments but declined to comment. Mr. Nishnic has long been the family spokesman and has remained close to his former father-in-law despite his divorce. He said he had not spoken with Demjanjuk about Thursday’s hearing.

“He’s old — he’s 87 years old, he’ll be 88 (in April) — he’s not in good health and we just told him, ‘Let us do the worrying and you just stay well, and we’ll get justice at the end of the day,'” Mr. Nishnic said. “The man was sent to Israel and sentenced to death for something he clearly didn’t do, that the government knew he didn’t do, and they got away with it — the government — so now we’re just coming back to our courts and trying to stop this proceeding,” Mr. Nishnic said. The Justice Department first brought charges in 1977 seeking to revoke Mr. Demjanjuk’s citizenship and to deport him for falsifying information on his applications when entering the U.S. in 1952 and to become a citizen in 1958.

His American citizenship was revoked in 1981, restored in 1998 and revoked again in 2002. He was extradited to Israel in 1986 and was under a death sentence, until Israel’s Supreme Court ruled in 1993 that he was not the same man as the guard known as Ivan.

The current deportation case is based on evidence uncovered by the Justice Department that Mr. Demjanjuk was a different guard. That evidence led courts to again strip Mr. Demjanjuk of his citizenship on the basis of the original falsified information.

Mr. Broadley disputes whether a former chief immigration judge, Michael Creppy, had authority to rule in December 2005 that Mr. Demjanjuk could be deported to his native Ukraine or to Germany or Poland.