WASHINGTON — In two courtrooms 200 miles apart on Tuesday, President Trump’s almost daily attempts to dismiss the criminal investigations that have engulfed his White House all but collapsed.
Mr. Trump has long mocked the investigations as “rigged witch hunts,” pursued by Democrats and abetted by a dishonest news media. But even the president’s staunchest defenders acknowledged privately that the legal setbacks he suffered within minutes of each other could open fissures among Republicans on Capitol Hill and expose Mr. Trump to the possibility of impeachment.
In Manhattan, Michael D. Cohen, the president’s former lawyer, admitted in court that Mr. Trump directed him to break campaign finance laws by paying off two women who said they had sexual relationships with Mr. Trump. And in Alexandria, Va., a jury found Mr. Trump’s former campaign chairman, Paul Manafort, guilty of eight counts of tax and bank fraud — the most significant victory yet for the special counsel, Robert S. Mueller III.
A president who has labored under the cloud of investigations from almost the moment he took office, Mr. Trump now faces an increasingly grim legal and political landscape. Mr. Mueller is methodically investigating whether Mr. Trump and members of his campaign conspired with a foreign power to win the election — and whether the president tried to obstruct the investigation from the White House. And the president is months away from congressional elections that could hobble the second half of his presidency.
Democrats seized on the judgments against Mr. Manafort and Mr. Cohen — they both face years in prison — to argue that Mr. Trump was suffused by a culture of graft and corruption, an argument that could prove powerful for an already galvanized party in the midterm contests.
Inside the West Wing, aides to Mr. Trump — numbed and desensitized by breathless news cycles blaring headlines about the president’s behavior — said privately on Tuesday afternoon that they were having trouble assessing how devastating the day’s legal events might be.
Mr. Trump’s advisers spent hours working on a statement that was attributed to his lawyer, Rudolph W. Giuliani, but privately several said they could not come up with something to explain away Mr. Cohen’s admissions beyond calling him a liar.
As he landed in Charleston, W.Va., for a rally with supporters on Tuesday night, a grim-faced Mr. Trump sidestepped questions about Mr. Cohen. He defended Mr. Manafort as a “good man” who had been ensnared in an investigation that ranged far beyond its original mandate.
“It had nothing to do with Russian collusion,” Mr. Trump told reporters. “We continue the witch hunt.”
Later, the president largely ignored the dramatic courtroom events during a raucous rally in which his fervent supporters cheered the president’s usual rants about trade, illegal immigration, Democratic obstruction and the news media.
“Where is the collusion? Find some collusion,” he said before shifting topics to declare that illegal immigration is “the beating heart” of the coming elections.
The impact of Mr. Manafort’s conviction and Mr. Cohen’s guilty plea on the investigation itself was unpredictable, according to legal experts. But Democrats said it put the lie to Mr. Trump’s argument that Mr. Mueller was engaged in a political investigation.
“It shows that Mueller and prosecutors in New York are conducting a professional investigation, following the facts where they lead, and obtaining serious felony convictions,” said Representative Adam B. Schiff of California, the senior Democrat on the House Intelligence Committee. “They also dramatically increase the likelihood that both men cooperate with the government.”
Mr. Schiff said Mr. Cohen’s admission that he violated campaign finance laws in paying hush money to two women “adds to the president’s legal jeopardy,” though Mr. Trump’s advisers played down the likelihood that a sitting president would be indicted for such violations.
“There is no allegation of any wrongdoing against the president in the government’s charges against Mr. Cohen,” said Mr. Trump’s lawyer, Rudolph W. Giuliani, in a statement. “It is clear that, as the prosecutor noted, Mr. Cohen’s actions reflect a pattern of lies and dishonesty over a significant period of time.”
Still, Mr. Cohen was blunt about the president’s culpability as he stood in court and admitted his guilt: “In coordination with, and at the direction of, a candidate for federal office,” Mr. Cohen said he conspired with a media company to keep secret Mr. Trump’s affairs with Stephanie Clifford, a pornographic film actress known as Stormy Daniels.
“Mr. Cohen, when you took all of these acts that you’ve described, did you know that what you were doing was wrong and illegal?” the judge asked. Mr. Cohen answered, “Yes, your honor.”
The startling charge directed at the president carried echoes of President Richard M. Nixon, who was named an “unindicted co-conspirator” in the special prosecutor’s investigation of Watergate.
And it raised the prospect that Mr. Trump’s presidency could be at risk by impeachment in Congress even if the sprawling Russia investigation never definitively concludes that there was collusion or obstruction of justice.
Mr. Cohen worked for decades as Mr. Trump’s personal lawyer and fixer. He was privy to the innermost details of the president’s business dealings and personal life — once saying he would take a bullet for him.
While Mr. Mueller’s investigation grinds on — reaching into the murky depths of Russian money laundering or Russia’s shadowy efforts to hack the 2016 election — Mr. Cohen’s case throws a white-hot spotlight on the behavior of Mr. Trump and his closest confidants.
It also makes it harder for Mr. Trump or his aides to distance themselves from Mr. Cohen’s wrongdoing. Though he also pleaded guilty to tax and bank fraud, related to his ownership of New York City taxi medallions, the heart of the case against Mr. Cohen is the payments to women he made on behalf — and at the behest of — his most celebrated client.
With Mr. Cohen’s plea, five associates of the president have either pleaded guilty or being convicted of crimes since Mr. Trump took office. In addition to Mr. Cohen, Mr. Manafort, and Mr. Flynn, they include Rick Gates, the former deputy campaign chairman, and George Papadopoulos, who advised the campaign on foreign policy issues.
Mr. Trump’s mood tracked a tumultuous day. In the morning, the president was chipper, monitoring Fox News and commenting to aides on the headlines he saw, according to people who spoke with him. But Mr. Trump was already snappish with aides in the West Wing before the Manafort verdict was announced and before Mr. Cohen pleaded guilty, according to people familiar with his conversations.
By then, it had become clear that Mr. Cohen was likely to plead guilty to several crimes. His churlish mood had not lightened by the time he boarded Air Force One for the rally in West Virginia, and learned the details of his plea.
The president’s team quickly tried to paint Mr. Cohen as a liar, and noted that prosecutors had not targeted Mr. Trump.
People close to Mr. Trump privately acknowledged that the declarations from Mr. Cohen, made under oath in open court, could have significant political ramifications.
While impeachment discussions have always been treated as having a potential positive impact to turn out Republican voters, the statements that Mr. Cohen made were stark and took it out of the realm of the theoretical.
“I think impeachment is now squarely going to define the midterms,” said Rob Stutzman, a Republican strategist who has been critical of Mr. Trump. “It’s inescapable now that Democrats can legitimately raise that issue.”
He added, “There’s a lot of Republican members of Congress sitting in tough districts that are going to have to really think hard about how they’re going to finesse this in the days ahead.”
What makes it harder for Republicans, he said, is that this did not emerge from the Mueller inquiry. “This isn’t something from the deep state,” he said. “This is a classic B team type of bumbling screw up of covering up mistresses.”
And, he added, “It’ll be very hard to distance the president. You would assume that there’s legitimate evidence that the president was aware that those invoices were not for services rendered. You already have the one tape.”
Brian Walsh, a former spokesman for the National Republican Senatorial Committee, said that it was too early to say whether this would damage the president, but he noted he is already suffering with suburban voters.
“I think the president’s most ardent supporters will continue to defend him with blinders on but to any neutral observer watching this, it’s impossible to believe that Cohen would engage in this conduct without his client signing off on it or at least being aware of it,” he said.
“I think many will take a wait-and-see attitude,” he added. “What it does is serve as another tremendous distraction for Republicans running for re-election and already facing tough political headwinds. Every day that Republicans are being asked about legal questions surrounding the president is a day they’re not delivering the message they want to be delivering on the campaign trail.”