When Russell T. Baker Jr. was chosen to be Maryland's new U.S. attorney, Baltimore applauded. He was an ideal selection, respected voices said, a prosecutor's prosecutor and a man whose record was so filled with achievements it only could be described as dazzling.

No one's opinion has changed. If anything, during the past three weeks on his new job Baker, 35, has enhanced his reputation as one of the most promising attorneys to come out of Maryland's criminal justice network.

He, however, has been acting as "interim" prosecutor, appointed temporarily by the judges of the U.S. District Court. Baker's nomination has yet to leave the White House where it has been stalled for over one month without an official explanation. "I really don't know why, it just takes a while," a spokesperson there said.

It is generally believed that until the controversy and obstruction of justice probe centering on the firing of David W. Marston fades away, Baker's nomination will stay in the White House. As deputy to Benjamin R. Civiletti at the Justice Department, Baker was the official who first learned of the possible involvement of a Congressman in the Philadelphia hospital investigation being conducted by Marston.

Baker's role in handling that investigation is being questioned by the same Congressional committee that must approve his nomination as U.S. attorney.

Baker is a golden boy the equal of an F. Scott Fitzgerald character. His father built one of the most successful real estate companies in the Baltimore area and gave his son and namesake private schooling from grade school through Harvard Law School where Baker made law review. He then clerked for Fourth Circuit Court of Appeals Judge Harrison L. Winter and Chief Justice Warren Burger. He had a happy childhood, he has a happy family now. "I've been lucky and I've worked hard," Baker explains.

Baltimore's legal community is let down because Baker was more a favorite among lawyers than politicians. The general feeling is that if he loses the nomination "lot of people will be very angry."

"The White House has no justification whatsoever in withholding (his) nomination," said George Beall, former U.S. attorney for Maryland and Baker's old boss. It was under Beall that Baker and two other Maryland federal prosecutors plotted the investigation of political corruption in Baltimore County and would up forcing then Vice President Spiro T. Agnew out of office.

"I think it's unfair to Tim (Baker's nickname) and reflects a lack of consideration for the needs of the U.S. attorney's office in Maryland. He stands head and shoulders above everyone else. If he doesn't get the nomination I'd be terribly disappointed," Beall continued.

Almost every other lawyer concerned about the federal prosecutor's job in Baltimore voiced the same opinion. At the same time they said they were afraid of "saying anything that would fuel the controversy and keep Tim from getting the nomination."

In spite of this Baker has made what one assistant in his office described as "a running start."

"I am the U.S. attorney," Baker explained. "I have been told to be the U.S. attorney and I have acted as one. I've filled all the vacancies in this office and there were five where I came."

Since he will be called to testify on the Marston controversy, Baker refused to comment on his role. He said only "I know I'm not lying and I know Civiletti well enough to know he's not lying. We have inconsistent recollections, that's all."

The key question is whether Baker told Civiletti that Rep. Joshua Eilberg (D-Pa.) might be involved in the federal investigation. Eilberg called President Carter asking for Marston's replacement after Marston told Baker of the involvement.

Civiletti said Baker failed to tell him Baker says he did. The committee hopes to discover why that connection wasn't discussed openly with U.S. Attorney General Griffin Bell and President Carter before Marston was fired.

As a federal prosecutor for three years, as a private attorney with the prestigious Piper and Marbury and as deputy to Civiletti, Baker was known for his ability to work and work and work. He is described as brilliant, someone with great powers of concentration and attention for detail. He has also been called arrogant.

"Arrogant, I wouldn't say arrogant I would say imperious," said an attorney who counts Baker as one of the handful of men he admires. Another, also a friend, said Baker "hasn't made enough mistakes and doesn't feel he will."

The problem, of course, is that Baker has not had major failures. During the Baltimore County investigation he took to avoiding the early morning weekly staff meetings because they were inconvenient and he claimed to have better things to do with his time.

One of those items was his initial suspicion that Agnew was "acting like a guilty man" and might be involved in the kickback schemes. His colleagues Barnet D. Skolnik and Ronald S. Liebman laughed at him.

The investigation led to Agnew's plea of no contest to a charge of income tax evasion.

Now, as U S Attorney in Baltimore, Baker has moved the staff meetings from early Wednesday morning to Friday afternoons.

From Agnew, to Maryland Governor Marvin Mandel's conviction, to the systematic investigation and prosecution of zoning offenses in Prince George's County, the U.S. attorney's office has become famous as one of the top in the country in the past decade.

"Would I dare disagree with the contention that Baltimore is now up with the Southern District of New York?" asked Mandel's lawyer, Arnold M. Weiner, formerly a federal prosecutor in Baltimore who now represents many of the defendants brought before that court.

"Baker," said Weiner, "has a quick sharp legal mind and is first rate. He'll inspire confidence because his ability will be respected, he brings his experience to the job and that has not always been the case."

Past U.S. attorneys in Baltimore have generally been political appointments who turned cut to be nonetheless aggressive. Joseph Tydings became a U.S. senator after his stint in that office. Beall is the brother of a former U.S. senator, Jervis Finnery, whom Baker will replace, was a Maryland state senator before he was named to the office.

A failed Republican candidate for Baltimore County executive, Finney took President Carter at his word when he promised to take the politics out of appointments for federal prosecutors. Like Marton, Finney hoped to stay on with the Democratic administration.

Another former U.S. Attorney Stephen H. Sachs is a front-running candidate for the Democratic nomination for Attorney General. It is a small clique that some fear has gotten inbred.

Baker discounts that complaint. He likens the office to a training institution producing attorneys for private practice and political life. Civiletti, for one, comes from the same tradition.

Now, the Senate committee is asking which, if either, of the Baltimore-bred attorneys is lying.

"Ben (Civiletti) and I wouldn't lie. When someone's lying there has to be a motivation. There is no reason for us to lie."