For the second time in recent months, a lawyer backed for a judgeship by some of Prince George's County's most powerful politicians has been eliminated from the competition by the southern Maryland Circuit judicial nominating commission.

John W. Wolfgang, a Democratic delegate to the General Assembly from Tantallon, had been backed by such county political notables as state Senate President Steny Hoyer and Peter F. O'Malley, a prominent lawyer and president of the Washington Capitals. In addition, Wolfgang is the brother-in-law of Maryland Secretary of State Fred L. Wineland.

Such weighty support, so important in past appointments, was not enough this time, however, Wolfgang finished fourth in the county bar association poll in a field of eight. The nominating commission, meeting Tuesday night in Upper Marlboro, also decided to send four other names to Gov. Marvin Mandel to fill two District Court vacancies.

"Political considerations alone are not sufficient to make someone a judge," said Lance Billingsley, chairman of the county Democratic Party.

In November, the nominating panel failed to send forward the name of District Court Judge Vincent Femia, who was seeking a Circuit Court seat with even wider political backing.

Both Femia and Wolfgang fell two votes short of the seven needed from the 13-member commission to be rated "legally and professionally most fully qualified." In Femia's case, there was a large outcry among many county lawyers and politicians because he wasn't rated as qualified. Not so with Wolfgang.

"He's a practicing attorney but his exposure to practice in Prince George's is somewhat limited," explained Billingsley. "In Vince's case, you had a sitting judge."

Wolfgang, chairman of the Assembly's Economic Matters Committee, told a reporter recently that he viewed the District Court seat he was seeking as "the training ground" for the Circuit Court, which "is the ultimate for me."

Questions were raised about Wolfgang's health - he had a heart attack in 1974 - and all official candidates were interviewed by the commission Tuesday night, the first time this has been done anywhere in the state. John A. Buchanan, the panel's chairman, said Wolfgang's health was "not a factor" in the commission vote.

Of the four names submitted to Mandel, two received ihe requisite support yesterday morning of the bi-weekly "breakfast club" of elected county Democrats and thus are expected to be named to the judgeships. They are Audrey Melbourne, a lawyer, who would be the first woman in county history to become a full-fledged judge, and Graydon S. (Skip) McKee III, a part-time juvenile court master.