A few miles south of the namesake tower where Donald Trump began his run for president, New York prosecutors are grinding away at an investigation into his business dealings that could shadow him long after he leaves office in January.

The probe led by Manhattan District Attorney Cyrus Vance Jr. is one of several legal entanglements likely to intensify when Trump loses power — and immunity from prosecution — upon leaving the White House.

Trump faces two New York state inquiries into whether he misled tax authorities, banks or business partners. Two women alleging he sexually assaulted them are suing him. Some Democrats are calling for the revival of a federal campaign finance investigation that appeared to end under U.S. Attorney General William Barr.

It isn’t known whether any investigation has gathered sufficient evidence to charge Trump with any crimes.

Prosecuting a former president would also be an unprecedented step in a country that has sought, since its founding, to sweep aside a departing commander-in-chief’s alleged transgressions in favor of a peaceful transition of power.

“With the country so sharply polarized in 2020, would a legal battle ultimately be seen as political retaliation? That is a difficult calculation,” said Meena Bose, executive director of the Peter S. Kalikow Center for the Study of the American Presidency at Hofstra University.

Trump has said that he has the “absolute right” to pardon himself for any federal offenses, but the concept remains untested because no president has ever attempted to do so. A 1974 Justice Department opinion said presidents could not pardon themselves because that would violate the “fundamental rule that no one may be a judge in his own case.”

Trump has used his pardon power to help out friends and high-profile defendants in the past, commuting the sentence of longtime friend Roger Stone in July and former Illinois Gov. Rod Blagojevich in February, and has suggested he could do more of the same before his term ends.

Vance’s investigation is particularly troublesome for Trump because it involves possible state-level charges that could not be wiped away with a presidential pardon.

Vance, a Democrat, hasn’t disclosed the details of his probe, citing grand jury secrecy rules, but his office has said in court filings that it is related to public reports of “extensive and protracted criminal conduct at the Trump Organization.”

Trump’s former personal lawyer and fixer, Michael Cohen, told Congress that Trump often inflated the value of his assets when dealing with lenders or potential business partners, but deflated them when it benefited him for tax purposes.

While Trump has been in office, the investigation’s progress has been hampered by court fights over whether prosecutors could get access to his tax returns, or whether a president has any immunity from a state investigation. One appeal related to the records battle is now before the U.S. Supreme Court.

Vance’s office declined to comment. It isn’t clear whether the long-running probe is close to conclusion, or months or years away from any resolution.

A message seeking comment was left with a lawyer for Trump. In the past, Trump has called Vance’s investigation “a continuation of the witch hunt — the greatest witch hunt in history.”

New York Attorney General Letitia James is also investigating whether Trump’s company lied about the value of its assets to get loans or tax benefits, though her probe is civil — not criminal — in nature. Trump’s son, Eric Trump, spoke by video with investigators last month after losing a court fight to postpone the deposition until after the election.

There were new revelations Thursday that both James and Vance had also subpoenaed documents related to tax deductions taken by Trump’s company related to business consulting fees paid to his daughter, Ivanka Trump.

Part of Vance’s criminal investigation pertains to payments made during Trump’s 2016 campaign to porn actress Stormy Daniels and model Karen McDougal to prevent them from publicly alleging they had extramarital affairs with him.

Cohen pleaded guilty to orchestrating the payments, which Manhattan federal prosecutors said amounted to illegal gifts to Trump’s campaign. They identified Trump in court filings as having directed Cohen’s efforts, but he was not charged. Trump has denied the affairs and said any payments were a personal matter, not a campaign expense.

The Justice Department has a longtime policy stating that it is unconstitutional to prosecute a sitting president in federal court.

There is also the potential that a Democrat-led Justice Department could pursue matters left uncharged in Robert Mueller’s investigation into Russian election interference, such as allegations Trump obstructed justice.

President-elect Joe Biden, a Democrat, has said that he would not direct his Justice Department to pursue charges against Trump — nor would he stand in the way of investigations it might take up on its own.

“I am not going to make that individual judgment,” Biden told reporters in August.

Some Democrats have cautioned that indicting Trump could enrage the nearly 74 million Americans who voted for him, complicating Biden’s promised effort to heal the nation’s political divisions. Former U.S. Attorney General Eric Holder, a Democrat, has warned of the “potential cost to the nation” from prosecuting a former president.

Richard Nixon was pardoned by his successor, Gerald Ford, after resigning in 1974 over the Watergate break-in in an effort by Ford to end the fallout from an all-consuming political scandal. Bill Clinton, on his final day in office, struck a deal with special counsel Robert Ray to avoid prosecution over perjury allegations that led to his impeachment. He agreed to give up his law license for five years and pay a $25,000 fine for lying in a sexual harassment lawsuit.

Paul Rosenzweig, a former senior counsel in the Clinton investigation, argues that potentially criminal behavior stemming from Trump’s time as a businessman would make him an exception to the practice of not prosecuting former presidents.

“Never before have we had a president, who has been credibly accused of criminal activity from before his presidency,” he said.

Once out of office, Trump won’t be able to point to his busy schedule as a reason to delay civil lawsuits, like ones brought by E. Jean Carroll, a former magazine advice columnist, and Summer Zervos, a restaurateur and contestant on his old TV show, “The Apprentice.”

Carroll says Trump raped her in the mid-1990s in a New York department store. Her lawsuit says Trump’s denial of the allegation — including that she was “totally lying” to sell a memoir — defamed her. Carroll is seeking a DNA sample from Trump to see if it matches material found on a dress she says she wore during the alleged attack.

Zervos says Trump kissed and groped her when she sought to talk to him about her career in 2007. Trump denied her allegations and retweeted a message calling Zervos’ claims a hoax.

Trump’s lawyers have maintained that Zervos’ defamation suit should be delayed until he’s out of office. That’s now only about nine weeks away.