New York is ground zero
The fears over potential political interference are particularly acute in New York, where prosecutors with the US attorney's office in Manhattan handle high-profile cases with a broad range of geopolitical implications, including terrorism prosecutions as well as investigations involving foreign governments and financial institutions, all of which can intersect with White House interests.
Manhattan prosecutors have also generated cases that are of concern to Trump personally, including the prosecution of Cohen and an investigation of the Trump Organization that ended without charges.
And for the past few months, prosecutors there have been investigating Rudy Giuliani, Trump's personal attorney, as well as Trump's inaugural committee.
Still, despite the alarm sounded in recent days, Southern District of New York prosecutors believe that their leader, Geoffrey Berman, has defended the office's relative autonomy, particularly since Barr's arrival, according to people familiar with the matter.
Barr, these people said, has attempted to micromanage certain cases, asking more questions and for more frequent updates than his predecessors on matters from Berman.
Berman has bristled at those demands, according to these people, and has repeatedly pushed for actions on certain politically sensitive cases in opposition to Justice Department leadership, most notably the indictment in October of the state-owned Turkish bank, Halkbank.
According to a person familiar with the discussions, Barr personally spearheaded an effort last year to negotiate a settlement with the bank that would have allowed it to sidestep an indictment after Turkey's President, Recep Tayyip Erdogan, pressed Trump in a bid to avoid charges. Berman, however, insisted on criminal prosecution, according to the people familiar with the matter.
A spokesman for the Manhattan US attorney's office declined to comment for this story.
Those types of actions have pacified Berman's staff in New York, who recall a message that Berman, a Trump appointee, delivered soon after taking his oath of office in 2018: "I want to be clear: Politics is not going to have a role in what we do. We're going to keep doing business as we always have."