President Trump’s nominee for deputy attorney general, at his confirmation hearing Tuesday, pushed back on Democratic calls to name an independent special prosecutor to oversee the Justice Department’s probe into Russian interference in the 2016 presidential campaign.

Democrats have shifted focus to nominee Rod Rosenstein in the wake of Attorney General Jeff Sessions recusing himself last week from any such investigations. If confirmed, Rosenstein would be the point person on the election interference investigation.

Sen. Dianne Feinstein, D-Calif., said at Tuesday’s hearing that Rosenstein has “impressive credentials” and she does not question his “integrity.” But she said, “We need steel spines and there is a real danger the Justice Department could become politicized.”

Rosenstein, though, said he is not aware of any circumstances that would demand his recusal, though he left the door open by saying he would become familiar with the evidence and reassess. But he would not commit to naming a special counsel.

“I’m not aware of any requirement for me to recuse at this time,” Rosenstein said, under separate questioning from Republican Sen. Charles Grassley.

Meanwhile, fellow Marylander, Democratic Sen. Chris Van Hollen, praised Rosenstein’s record as U.S. attorney for Maryland and backed his nomination. But he also called for a special prosecutor and said Rosenstein should be “willing to put his job on the line to uphold the values of the Justice Department.”

Interviews with former colleagues and attorneys who know Rosenstein professionally all say he is a prosecutor that will work to defend the integrity and the independence of the Justice Department. And they don’t expect him to bend to political pressure, from either side of the aisle, on a special prosecutor with broad jurisdiction to investigate alleged Russian influence on the election.

“He may well decide to appoint a special prosecutor -- and if he does, it won't be because a senator demanded it during a confirmation hearing,” said former DOJ attorney Jason Weinstein, who worked with Rosenstein during the Bush and Obama administrations. “And it won't mean he lacks confidence in DOJ's ability to do the investigation right. It would be because he concludes it's the right thing to do for the Department and for the public's confidence in the integrity of the investigation. This is a partisan minefield no matter what he decides, but partisanship won't be part of the equation for him.”

In explaining why she’s already calling for a special prosecutor, Feinstein said, “People have to trust … this investigation does not have even the appearance of conflict of interest.”

Republicans like Sen. John Cornyn of Texas were skeptical of the Democrats’ intentions. “I’m confused that after praising Mr. Rosenstein’s credentials, the Democrats immediately went on to call for an independent investigation,” he said.

Rosenstein said he has not spoken with Trump or Sessions about the possibility of appointing a special prosecutor, but he’s “willing to appoint a special counsel whenever I deem it appropriate based on the policies and procedures of the Justice Department.”

Rosenstein has a long track record in high-profile cases that could bolster his reputation for independence.

As a young attorney in the 1990s, Rosenstein was tapped to join Kenneth Starr’s team of prosecutors investigating shady Clinton real estate dealings in Arkansas.

Former Attorney General Eric Holder appointed Rosenstein to investigate who was leaking classified information about the Obama administration’s role in cyberattacks against Iran. The DOJ later reached a guilty plea with retired Marine Gen. James Cartwright for making false statements about a covert cyberattack on Iran’s nuclear facilities. The New York Times decried the result, saying it would have a chilling effect on government employees leaking to the press.

Outside the Beltway scandals, Rosenstein also has prosecuted local corruption cases, including against former Prince George’s County Executive Jack B Johnson, who received a seven-year term for extortion and witness- and evidence-tampering. Rosenstein also has prosecuted allegedly corrupt Baltimore cops along with vicious gangs like MS-13.

“The Maryland criminal defense bar knows that knowing Rod will get you nowhere when it comes to trying to influence decisions in his office. He simply does what is right and just and does not take personal relationships into account,” said Baltimore criminal defense attorney Steve Silverman, who has known Rosenstein professionally for years.

Weinstein said, “Regardless of his title and his position, he makes decisions the same way he did during his decades as a career prosecutor. That means following the facts wherever they lead, pursuing justice, and doing the right thing -- without regard for politics.”