ANALYSIS — By striking a plea deal, Michael Cohen essentially signed a disloyalty pledge to his former boss: Donald Trump. And it should give the president ample reasons to sweat.

Cohen pleaded guilty Tuesday in a surprise hearing in New York to multiple campaign finance, bank fraud and tax fraud charges. The hearing culminated several weeks of the former “fixer” and his team publicly criticizing Trump — and the president firing back.

Trump reportedly has grown agitated in recent weeks that Cohen could attempt to ward off a stiffer penalty by providing federal investigators damaging information about his business and political dealings.

“Not a good day for the president. It may be that there is a likelihood that Cohen wishes to cooperate,” Richard Serafini, a former Justice Department attorney, told Roll Call on Tuesday.

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Trump and his personal lawyer, Rudolph Giuliani, have tried to distance the president from his former “fixer,” but the optics of Cohen’s admission of guilt alone are bad for the president — though he has a Teflon quality that allows him to absorb body blows and maintain the support of about 40 percent of the U.S. electorate. Still, here are three reasons the president should worry about Cohen’s deal.

A bigger fish?

Cohen worked for Trump for years, and was the now-president’s go-to man to clean up messy situations and do the dirty work. That means Cohen would know if there are any skeletons in Trump’s business or 2016 campaign closets.

Legal analyst Jeffrey Toobin told CNN it is difficult to fathom that prosecutors would strike this kind of deal with someone like Cohen and then never again question him. Typically, federal investigators will offer a plea deal in return for information about a “bigger fish,” said Toobin, though he noted it is not year clear that would automatically be Trump.

“The question becomes is Cohen in a position to have information that would be helpful to the special counsel,” Serafini said, referring to Robert S. Mueller III, the former FBI director leading the Justice Department’s Russia election meddling probe.

Campaign questions

Trump and his team have long — and loudly — denied his 2016 campaign colluded or had illegal contacts with the Russian government or other Russians. But that’s not what the U.S. attorney was looking at when it came to Cohen.

And that means his admitting campaign finance violations raises the possibility he already has told federal investigators — maybe even Mueller — about illicit actions Trump’s campaign took during the last presidential election cycle. If the campaign violated campaign finance laws and Trump was involved, his former “fixer” likely knew about it.

“The fact that Michael Cohen is pleading guilty is just an enormous development in the history of the Trump presidency,” Toobin said. “Almost no one knows more of his secrets.”

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Serafini said “at its worst,” for Trump, Cohen “could provide evidence of election law violations and Trump’s knowledge of bank fraud and election violations.”

Stormy waters ahead?

Trump and one of his new attorneys — in a stunning reversal — admitted in early May that he reimbursed Cohen for a payment made to adult film actress Stormy Daniels.

Giuliani said the president repaid his “fixer” $130,000 he transmitted to Daniels (real name Stephanie Clifford) in return for her silence about an alleged sexual encounter when Trump was a reality show star. The former U.S. attorney and New York City mayor has said the payment and alleged reimbursement will “turn out to be perfectly legal.”

“That money was not campaign money. … No campaign finance violation,” he said. But some legal experts say Giuliani’s comments failed to clear up campaign finance violation questions.

“He’s most likely in a position to provide details on the Stormy Daniels and Karen McDougal payoffs,” Serafini said of Cohen.

Michael Avenatti, Clifford’s lawyer, tweeted Tuesday that Cohen’s plea will “permit us to proceed with an expedited deposition of Trump under oath about what he knew, when he knew it, and what he did about it.”

The developments of today will permit us to have the stay lifted in the civil case & should also permit us to proceed with an expedited deposition of Trump under oath about what he knew, when he knew it, and what he did about it. We will disclose it all to the public.

— Michael Avenatti (@MichaelAvenatti) August 21, 2018

Avenatti also used the development to send a message to Giuliani: “Buckle Up Buttercup. You and your client completely misplayed this…”

.@RudyGiuliani Buckle Up Buttercup. You and your client completely misplayed this… https://t.co/peLpswrDO1

— Michael Avenatti (@MichaelAvenatti) August 21, 2018