Two were powerful House committee chairmen, two obscure congressmen from working-class districts in Philadelphia. All were captured by the FBI's secret Abscam cameras, and today a federal judge sentenced them to prison.

After nearly two hours of defense arguments that ranged from pleas for mercy to open defiance, U.S. District Court Judge George C. Pratt sentenced former Reps. John M. Murphy (D-N.Y.), once head of the House Merchant Marine and Fisheries Committee, Michael (Ozzie) Myers, and Raymond F. Lederer, both Philadelphia Democrats, to three years in jail and fined them $20,000 each for their Abscam corruption convictions.

Pratt also sentenced former Rep. Frank Thompson Jr. (D-N.J.), longtime head of the House Administration Committee, but delayed setting the final prison term and fine pending a post-appeal report on his medical condition. A doctor fears a prison term "might well kill" the 63-year-old Thompson, his attorney said. In an attempt to get leniency for Thompson, former president Gerald Ford wrote Pratt praising his old adversary.

Two of Myers' co-defendants, Philadelphia city councilman Louis C. Johanson, and former Camden, N.J., mayor Angelo J. Errichetti, also were sentenced today. Johanson, whose son committed suicide because of Abscam, according to his lawyer, was sentenced to three years in prison and a $20,000 fine.

Errichetti, the unknowing middleman who introduced several members of Congress to undercover FBI agents posing as representatives of an Arab sheik, was sentenced to six years in prison and fined $40,000, double the penalties of the former congressmen. Sentencing for another middleman, Philadelphia lawyer Howard L. Criden, was postponed because he recently suffered a serious heart attack.

All the defendants said they plan to appeal so it is expected to be at least a year before any prison sentence begins. Under parole guidelines none of those sentenced today will serve more than 20 months, defense attorneys said.

Murphy, the only one of the Abscam congressmen not convicted of bribery charges, stoutly proclaimed his innocence today, as he has throughout the 18 months the nation's most sweeping congressional scandal has been public.

He alone accepted Pratt's invitation to join his attorney's pre-sentencing statement. He read a prepared statement blasting the government's conduct in the case. Abscam's "criminal excesses," he said, "transcend the very crime it is supposed to stop, injure innocent people and lay the groundwork for the supreme domination of . . . the executive branch which controls the police function."

In an apparent slap at Pratt's rejection of his motions on government misconduct and his appeals, Murphy also said the absurdity of the government's conspiracy theory would become apparent "under more mature scrutiny." His attorney, Michael E. Tigar, said the case raised the moral question of what the "federal police and prosecutors ought to do and not what they are able to do."

The unusual joint sentencing of defendants from three separate Abscam cases came nearly a year after Myers' trial began. The delay was caused by Pratt's consideration of claims that the constitutional rights of the congressmen were violated by FBI agents offering undercover bribe offers in return for promises of immigration help for a fictitious "sheik."

Sen. Harrison A. Williams Jr. (D-N.J.) and former Reps. John Jenrette (D-S.C.) and Richard Kelly (R-Fla.) also were convicted on Abscam bribery charges, but haven't been sentenced pending decisions on their charges of government misconduct.

The sentencing attracted a large crowd to the courtroom at the federal courthouse in Brooklyn. As happened so often during the trials, the former congressmen had to run a gantlet of television cameras, microphones and shoving reporters and technicians to enter the building. Myers, in sunglasses and a tan suit, yelled, "Don't knock me down," as he pushed in. Murphy, 55, who now runs his family trucking business on Staten Island, approached the throng hand-in-hand with his wife.

In his plea for mercy to the judge, Myers' attorney, Neil Jokelson, described his client's 16-foot-wide row house in Philadelphia and his background as a longshoreman with a 10th-grade education. Prison would be traumatic for his three children, he said. Myers, 38, had been disgraced enough already, he argued, as the first member to be expelled from Congress since the Civil War.

Lederer's attorney, James Binns, said only that his client was "deeply contrite." Lederer was the only Abscam congressman to be reelected, but he resigned after his conviction rather than face possible expulsion by the House. He has worked recently as an ironworker.