Rod J. Rosenstein had dedicated most of his career to prosecuting fraud, corruption and other white-collar crimes before he was tapped to lead the U.S. Attorney’s Office in Maryland in 2005.

“It was a challenging time for the office,” Rosenstein recalled. “Violent crime was at near-record levels in Baltimore City and had been for some time, and of course it was the post-9/11 era.”

Much of his experience didn’t directly align with the state’s safety priorities, but he began to expand his expertise and reorganized his team to take on violent crime while holding steady on his longtime pursuit of public corruption. A Republican appointee, Rosenstein remained in the job for 12 years — through a Democratic administration.

Those management skills, the bipartisan history and his low-key, precise demeanor are what he now takes to the job of deputy attorney general under Attorney General Jeff Sessions.

Stephen M. Schenning will serve as Maryland’s acting U.S. attorney until President Trump nominates, and the Senate confirms, someone to permanently fill the position.

Days before the Senate confirmed Rosenstein to the second-highest position in the Justice Department, Rosenstein, 52, discussed the work he did in Maryland from his office in downtown Baltimore. He comes to the job as the department is expected to tackle major issues including drug enforcement and mandatory-

minimum sentences, violent crime in cities and the high-profile investigation of Russia’s ties to Trump associates during the 2016 campaign.

Rosenstein has confronted many similar issues firsthand as U.S. attorney.

[Grilled on Russia probe, deputy attorney general pick sidesteps Democrats’ calls for special prosecutor]

In Maryland, where Gov. Larry Hogan (R) has declared a state of emergency to fight the opioid crisis, Rosenstein’s office worked closely with federal and local law enforcement to target drug distributors. Overdose fatalities are now investigated as homicides, not suicides, with law enforcement searching for evidence that leads to sources and sellers.

“If you think about the traditional view, you have someone who overdosed on drugs and you’d think, ‘Well, it’s their own fault because they took too many drugs,’ ” Rosenstein said. “But if the drug that they’re taking is illegal and a drug they shouldn’t have had, then someone committed a crime by giving them that drug.”

Since 2015, the Maryland Attorney General’s Office — working with the U.S. Attorney’s Office and other federal law enforcement — has indicted more than 50 drug traffickers. The idea is to disrupt the supply chain to prevent further harm, particularly from a particularly powerful batch of drugs that can set off a string of overdoses, he said.

“The opioid crisis is about people dying from the drug,” Rosenstein said. “The crack wars were about people dying from bullets, largely as the result of criminal organizations warring over turf because they were trying to make money selling the drug.”

Rod Rosenstein before the Senate Judiciary Committee on March 7 (Melina Mara/The Washington Post)

Rosenstein is expected to play an important role in determining how the Justice Department handles drug-charging policies and the use of mandatory-minimum sentences. Sessions has indicated that his office will pursue mandatory minimums as it clamps down on gun and drug crime, possibly undoing Obama administration policies that considered such sentences discriminatory against minorities and low-level drug offenders.

In some cases in Maryland, Rosenstein said, mandatory minimums were a “valuable tool.” When applied appropriately, he said, they can stop offenders from committing more crime and induce people to share information about other criminal activity.

[Jack Johnson, former Prince George’s executive, sentenced to 7 years for corruption]

“A career criminal is not going to be persuaded to cooperate out of some sense of patriotism,” Rosenstein said. “We’ve had cases where people have come in and cooperated, and they might have information that allows us to resolve a dozen murders or more because they’re facing a mandatory minimum.”

In Baltimore, violent crime dropped 15 percent over Rosenstein’s first 10 years in office.

But enforcement alone wasn’t enough to address crime, he said. He also wanted the office to focus on community and direct outreach.

Borrowing an idea from Virginia and other offices, Rosenstein worked with local law enforcement and social agencies to develop a “call-in” program. Likely recidivists were brought in to speak with police and prosecutors, who gave warning lectures about the consequences of getting caught with guns. The program helped drive down shootings and homicides in the city over a six-year period, according to former federal prosecutors for Maryland.

Those attending the meetings would be connected to such resources as information on jobs or housing opportunities.

“In some cases, I felt sorry for these career criminals,” Rosenstein said. “They had been repeatedly prosecuted in the state system and had gotten light sentences. When they sat down in front of our federal prosecutor,” they were told, “Hey, because of your crimes and the volume of drugs you were dealing and the fact that you had a gun, you’re facing a mandatory sentencing of 10 to 20 years in prison in federal court.”

[This man could soon be handling America’s most politically charged investigation]

Rosenstein’s roots in public-corruption investigations reach to the days when he was one of the Whitewater prosecutors investigating Bill and Hillary Clinton’s real estate dealings in Arkansas in the 1990s.

His office prosecuted former Prince George’s county executive Jack Johnson for bribery and brought cases in a scheme in which more than a dozen Baltimore prison guards helped a notorious gang traffic drugs, launder money and order criminal activity from behind bars. More recently, his office announced the indictment of seven Baltimore police officers and the breakup of a pay-to-play scandal involving former Maryland politicians and the Prince George’s liquor board.

“That has not been an accident,” Rosenstein said of his focus on corruption. “It’s because we’ve had people committed to those cases who have exceptional experience.”

Before packing and leaving Baltimore, the Bethesda resident pointed out meaningful items that filled his offices: a photo of his two young daughters — now teenagers — in matching blue dresses and hair bows; an image of Rosenstein in his 20s, grinning with a chisel and hammer as he chipped away at the Berlin Wall; and framed printouts of meaningful quotations.

One he reflects on often is from a 1940 speech that U.S. Attorney General Robert H. Jackson gave describing the qualities of good prosecutors.

“The citizen’s safety lies in the prosecutor who tempers zeal with human kindness, who seeks truth and not victims, who serves the law and not factional purposes, and who approaches his task with humility,” part of the passage reads.

Rosenstein said, “It means that before filing charges, we should pause and ask, ‘What if we are mistaken?’ ”