Several investigations taking place in New York are quickly becoming what experts describe as the biggest threat to President Donald Trump.

The US attorney for the Southern District of New York, the New York attorney general, and the Manhattan District Attorney's Office are all either investigating Trump, his businesses, or his business associates, or are contemplating such investigations.

So far, local, state, and federal officials in New York are looking into hush payments that Michael Cohen, Trump's former longtime lawyer, made on Trump's behalf; how the Trump Organization was involved in those payments; the operations of the Donald J. Trump Foundation; and whether Trump's business practices in New York violate the Constitution's emoluments clause.

It's quickly becoming clear to experts that the multiple investigations going on in New York are the greatest threat to President Donald Trump.

Late last month, in a courtroom in lower Manhattan, Trump's former longtime lawyer, Michael Cohen, cut a deal with federal prosecutors and pleaded guilty to five counts of tax evasion, one count of making a false statement to a financial institution, and two counts related to campaign-finance violations.

The latter two charges were in connection to payments to the former Playboy model Karen McDougal and the adult-film actor Stormy Daniels to silence their allegations of affairs with Trump. And Cohen said under oath that Trump directed him to make the payments in order to boost his candidacy, making the president what experts called an "unindicted co-conspirator."

Soon after Cohen pleaded guilty, reports emerged that the Trump Organization CFO Allen Weisselberg and the National Enquirer boss David Pecker — two men with intimate knowledge of the hush payments — were given immunity by federal prosecutors investigating Cohen.

It's not clear exactly how much the immunity deals cover, or what prosecutors in the Southern District of New York plan to do regarding the payments moving forward. News reports suggested that the information Weisselberg provided was limited to the Cohen investigation and not connected to broader scrutiny of the president's or his business' finances.

But other New York investigative bodies are taking aim at the president and his business — or considering doing so.

A quagmire of investigations into Trump's businesses and associates

Michael Cohen. Yana Paskova/Getty Images

After federal prosecutors laid out how the Trump Organization reimbursed Cohen for his hush-money efforts, The New York Times reported that the Manhattan District Attorney's Office was weighing possible criminal charges against the Trump Organization and two unnamed senior officials.

The US Attorney's Office for the Southern District of New York listed those two unnamed Trump Organization executives in an information it filed in the Cohen case, accusing them of improperly accounting the hush-money reimbursements.

Then it was reported that Cohen was subpoenaed in a separate investigation, the New York state probe into the Donald J. Trump Foundation.

In June, acting New York Attorney General Barbara Underwood filed a lawsuit against Trump, his adult children, and the foundation following an investigation that began in 2016.

Underwood is accusing the foundation of engaging in illegal political coordination with Trump's campaign, making multiple self-dealing transactions to benefit Trump and his business interests, and violating legal obligations for such nonprofits in New York. She also sent referral letters to the IRS and the Federal Election Commission identifying possible violations of federal law for the agencies to investigate.

Trump and his business said the lawsuit was the result of political bias, and his attorney last week sought to have it thrown out on those grounds.

Soon after Underwood filed the civil suit, New York's Democratic governor, Andrew Cuomo, escalated the state's legal battle regarding Trump and his charity by opening the door to a potential criminal case against the nonprofit.

"At Gov. Cuomo's direction, the state stands ready to provide the [New York] Attorney General with the appropriate criminal referral on this matter if and when she asks for it," Alphonso David, the governor's counsel, said in a statement.

That statement was related to the New York State Department of Taxation and Finance's opening an investigation into the charity. If Cuomo feels that what turns up as a part of that probe is worthy of a criminal referral, he'll provide one to Underwood, who would need that to file a criminal lawsuit.

Trump's state tax returns could be made public as a result of that process.

Then-Republican Presidential hopeful Donald Trump leaves Manhattan Supreme Court where he was serving on jury duty on August 17, 2015 in New York City. Andrew Burton/Getty Images

On top of all that, Underwood is additionally investigating whether Trump's business practices in New York violate the emoluments clause, an arcane portion of the Constitution that prohibits public officials from receiving gifts or payments — known as emoluments — from foreign or state governments without congressional approval.

And Underwood's office is in touch with other law-enforcement agencies about Cohen's plea deal.

Amy Spitalnick, a spokeswoman for the attorney general, said that the office "has repeatedly and successfully acted to hold Donald Trump accountable for unlawful and unconstitutional actions, and we will continue to do so," pointing to the investigation into possible violations of the emoluments clause.

Of the Trump Foundation lawsuit, Spitalnick said: "We will hold Donald Trump and his associates accountable for violations of state law, and will seek a criminal referral from the appropriate state agency as necessary."

Combating Trump and his administration has been at or near the top of the agenda for both Underwood and her predecessor, Eric Schneiderman, who for years had a contentious relationship with Trump. Schneiderman resigned from office earlier this year after he was accused of abusing women.

'The New York state and local investigations add fuel to that fire'

Andrew Cuomo. Thomson Reuters

Alan Dershowitz, a professor emeritus at Harvard Law School and an informal Trump adviser who often provides legal analysis defending the president, told Business Insider in an email that he's "said for months" that New York provides the greatest danger to Trump.

During a recent appearance on ABC's "This Week," Dershowitz said he believes Trump "has constitutional defenses to the investigation being conducted by" Robert Mueller, the special counsel investigating Russian interference in the 2016 US presidential election and whether the Trump campaign was involved.

"But there are no constitutional defenses to what the Southern District is investigating," Dershowitz added. "So I think the Southern District is the greatest threat."

Mitchell Epner, an attorney at Rottenberg Lipman Rich who was formerly a federal prosecutor in the District of New Jersey, told Business Insider in an email that he believes "the various New York investigations, particularly the SDNY investigation in the aftermath of the Michael Cohen guilty plea, pose the greatest threat to President Trump."

"The New York state and local investigations add fuel to that fire," he said.

Roland Riopelle, a partner at Sercarz & Riopelle and a former federal prosecutor in the Southern District of New York, seconded that.

"Yes, at this point — and particularly with the immunity agreement with Weisselberg — New York is the biggest threat to Trump," he said.