Under Sen. Jeff Sessions, the Alabama Republican reported to be President-elect Donald Trump’s choice for Attorney General, the Justice Department — like much of the federal government — is poised to undergo a radical shift. The great majority of criminal prosecutions take place at the state level: About 211,000 people are locked up in federal prisons, compared with 1.3 million in state prisons, according to this useful chart from the Prison Policy Initiative. But Sessions would set the agenda on who faces the full might of the federal government, including — if some Trump supporters get their way — Hillary Clinton.

Trump himself can quickly eliminate criminal justice changes put into place by executive order, such as banning solitary confinement for juveniles in federal prison or directing federal agencies not to ask about criminal backgrounds in job applications. Here’s a look at what Sessions, a former U.S. attorney and state attorney general in Alabama, could change at one of the nation’s most powerful agencies:

Police oversight. President Obama’s Justice Department has made liberal use of its powers to investigate law enforcement agencies accused of a “pattern or practice” of violating civil rights. The Obama DOJ began 23 investigations and entered 11 consent decrees mandating reforms in Chicago, Baltimore, Cleveland and other cities, far more than Presidents Clinton or George W. Bush. In the introduction to a 2008 paper published by the Alabama Police Institute, Sessions condemned such interventions as an abuse of federal authority. “Consent decrees have a profound effect on our legal system as they constitute an end run around the democratic process,” he wrote. One caveat: Recent high-profile shootings by police may make it harder to dismiss the idea of oversight. Robert N. Driscoll, deputy assistant attorney general in the Civil Rights Division under George W.Bush, predicted the Justice Department will keep police reform alive, especially in an age where social media amplifies the concerns about racial disparities in policing. "There will be the same political pressure to open a 'pattern or practice,'" Driscoll said.

Sentencing. The attorney general guides U.S. attorneys — the top federal prosecutors appointed by the president — toward stricter or more lenient sentences through so-called charging memos. While individual U.S. attorneys have some discretion, “it is a philosophy you try to live up to because it’s your boss,” said Kevin Ring, a longtime Republican aide who is now vice president at Families Against Mandatory Minimums. Former Attorney General Eric Holder advised against piling up charges for low-level drug offenders and seeking maximum sentences, a policy Sessions is unlikely to continue. Sessions was a longtime supporter of eliminating sentencing discrepancies between crack and cocaine offenders, but he helped block broader drug sentencing reform in the Senate this year despite wide bipartisan support, saying it would release “violent felons” into the street. DOJ’s Office of Legislative Affairs can have significant influence on criminal justice measures in Congress, and Justice has a seat on the U.S. Sentencing Commission, which researches and develops guidelines on appropriate punishments.

Private prisons. In August, DOJ announced that its corrections subsidiary, the Bureau of Prisons, would phase out the use of private, for-profit prisons, after an inspector-general report found lapses in safety, security and oversight. Candidate Trump told Chris Matthews in June “I do think we can do a lot of privatizations and private prisons. It seems to work a lot better.” In October, Geo Group, one of the largest private prison corporations, hired two former Sessions aides to lobby in favor of outsourcing federal corrections to private contractors, according to Politico Influence.

Immigration. As a senator and Trump advisor, Sessions has been right in tune with the president-elect on the need to secure the borders, limit legal immigration, and expel many, if not all, undocumented immigrants. Enforcement is divided between the Departments of Homeland Security and Justice. The DOJ’s Executive Office for Immigration Review administers the nation’s immigration courts, appoints the judges who preside there, and oversees appeals of deportation orders. DOJ decides whether to bring criminal charges against those here illegally. Justice also could also use the threat of withholding federal money to pressure the 300 so-called “sanctuary cities” that have refused to assist in the identification and pursuit of the undocumented.

Local grants. The Justice Department doesn’t control state criminal justice policy, but it does have a multi-billion piggy bank to influence local initiatives. The agency’s Office of Justice Programs has more than $2 billion to fund programs on a wide range of issues, from forensics to domestic violence to body cameras for police. The priorities could shift under Sessions more toward law enforcement and away from measures intended to prevent crime or rehabilitate prisoners, said one former high-ranking Justice Department official who worked under former President George W. Bush. “The Attorney General can impact where DOJ money goes around research, pilot programs, all those things,” the official said.

Punishing leakers/whistleblowers. The Obama Administration has taken a hard line against government employees who reveal classified information to journalists, and has occasionally tried to force journalists to reveal their sources. The DOJ has stopped short of prosecuting journalists for publishing sensitive information, resisting calls from conservatives to invoke the Espionage Act against news organizations. Where Sessions would draw that line is unclear. During a 2013 Senate debate on a so-called federal shield law (giving journalists the protections already operative in most states) Sessions was an outspoken opponent, declaring, “This legislation, in effect, says we are going to create a legal mechanism to protect anyone who is going to call himself a newsperson.” One leading press lawyer described Sessions as “obstructionist as possible” to the bill’s passage. Sessions has not been an enthusiast for expanding government openness — but neither is the Obama DOJ.

War on drugs. Sessions vigorously prosecuted drug crimes as a prosecutor, and has bemoaned what he believed was a lack of attention to the issue by the Obama administration. "The prison population is declining at a rapid rate...And at the same time, the drug use is surging and death are occurring. And on my opinion, it's going to get worse," Sessions said in March in response to news that Obama’s DOJ was prosecuting fewer but “more serious” drug cases. It is unclear how a Justice Department under Sessions would handle prosecutions in the growing number of states that have legalized marijuana, which the federal government still classifies as a dangerous Schedule 1 drug.

Public defenders and bail. The Justice Department has traditionally left indigent defense up to the states, but the Obama administration, especially in its second term, has weighed in far more aggressively, often by filing “statements of interest” in local cases involving the right to counsel. The briefs have been effective in convincing judges to rule in favor of defendants who had been denied a lawyer. But the practice has been highly unpopular with prosecutors and municipal attorneys, who feel attacked. Barry J. Pollack, president of the National Association of Criminal Defense Lawyers, said the new administration could bow out of such efforts or “worst-case scenario, start defending these places that have failed to provide counsel to the poor.” Sessions took aim this year at the “agenda” that a public defender and civil rights attorney would bring to a judicial appointment, but also expressed support for federal defenders hurt by a 2013 budget sequester. DOJ has also submitted briefs in support of lawsuits challenging money in the bail system. “I would assume they won’t get involved in any more of these bail cases, but that remains to be seen,” said Jeff Clayton, policy director for the American Bail Coalition, a trade group for insurance companies that underwrite bail.