The Justice Department's Public Integrity Section has a storied 34-year history of pursuing corruption in government and safeguarding the public trust.

That trust was breached, however, when some of the unit's prosecutors failed to turn over evidence favorable to the defense in their high-profile criminal trial of Sen. Ted Stevens, R-Alaska, who died earlier this month in a plane crash.

Now Jack Smith, a 41-year-old prosecutor with a love for courtroom work and an impressive record, has been brought in to restore the elite unit's credibility.

Before Stevens, Public Integrity's renown was built on large successes — like the prosecution of the Jack Abramoff lobbying scandal and convictions of federal and state judges, members of Congress and state legislators, military officers, federal lawmen and bureaucrats and their state counterparts over the years.

But its stumble — not disclosing exculpatory evidence as Supreme Court precedent requires — was equally large. It was so serious that Attorney General Eric Holder, one of Public Integrity's distinguished alums, stepped in and asked a federal judge to throw out Stevens' convictions.

At the time of the Stevens debacle, Smith was overseeing all investigations for the international war crimes office at The Hague in the Netherlands. He'd read about the Stevens case. Offered the chance to take over Public Integrity, he couldn't stay away.

"I had a dream job and I had no desire to leave it, but opportunities like this don't come up very often," Smith said in an interview. "I left the dream job for a better one."

Smith said he arrived with an open mind, and "I found the unit I inherited operating at a high level. I have no excuses if we don't achieve great things."

Smith sees his job as serving people like his parents and the values they instilled as he grew up in the upstate New York town of Clay: "They pay their taxes, follow the rules and they expect their public officials to do the same."

Smith is in charge of politically sensitive criminal investigations he will neither discuss nor even acknowledge. They are known to include a probe of whether Sen. John Ensign, R-Nev., conspired with an ex-aide to violate lobbying restrictions.

A Harvard Law School graduate, Smith's first legal job was in the Manhattan district attorney's office.

"There were 40 or 50 of us who started together and all of us thought we wanted to be trial attorneys," Smith recalls.

Smith was among those still standing after the baptism by fire all young prosecutors face: Being on your feet in a courtroom, getting yelled at by judges and dealing with the daily pressures prosecutors face, but which a few, including Smith, seem to embrace.

"I don't think I was very talented, but you field a lot of ground balls, you're a good shortstop," says Smith.

Accounts of Smith's work ethic are legion. He spent a weekend sleeping in the hallway of a New York apartment building so he could intercept a victim who was afraid to testify in a domestic violence case. After what Smith calls "a long, long talk," the woman took the stand.

Smith's next stop was the U.S. attorney's office in Brooklyn, where he was in command of some of the most high-profile cases in the city, including prosecution of police officers in the sodomy of Haitian immigrant Abner Louima.

In a murder-for-hire trial that appeared to be a long-shot for prosecutors, Smith put the defendant's brother on the stand, a hostile witness. The story the brother told conflicted on a key point with the story the defendants' lawyers had been presenting — a difference Smith highlighted with devastating effectiveness. Jurors took two hours to return a guilty verdict, and one of them jokingly called across the street to Smith afterward outside the courthouse: "Will you be my lawyer?"

But he's had setbacks too: In a recent 2-1 decision, a federal appeals court dismissed a death sentence Smith won against a man for killing two New York police officers. The majority found Smith violated defendant Ronell Wilson's constitutional rights by suggesting to the jury during the trial's penalty phase that Wilson's decisions to exercise his rights to go to trial and to not testify should call into question Wilson's post-conviction expression of remorse. The dissenting judge said an error, if there was one, had no effect on the jury.

The head of Justice's criminal division, Assistant Attorney General Lanny Breuer, praises Smith's work: "I have the best guy I could have in that job. I'm looking for a natural leader, someone with tremendous energy, someone with tremendous judgment."

Repercussions from the Stevens case still echo.

The section's conduct is under investigation by a court-appointed special prosecutor and an internal Justice watchdog unit. Smith's predecessor, William Welch, and three members of the trial team left for other criminal division jobs. The 30-member office is pursuing scores of investigations. Each year the section charges dozens of people and assists U.S. attorneys around the country in hundreds of other cases.

But when the facts don't warrant a prosecution, "you have to be able to admit that if it's not there, it's not there," Smith said. "I think that's hard for people to do and having been a prosecutor for 15 years that is something I can do."

And something he has done repeatedly in recent months: He closed long-running investigations of former House Majority Leader Tom DeLay, R-Texas; Rep. Don Young, R-Alaska, and former Rep. John Doolittle, R-Calif. without charges. And adhering strictly to policy, Smith left it to the other side to disclose the closures.