No day during President Donald Trump’s 19 months in office could prove as dangerous or debilitating as Tuesday. Everything that happened in a pair of courtrooms hundreds of miles apart strengthened the hand of special counsel Robert Mueller and weakened that of the president of the United States.

This was a day when truth overran tweets, when facts overwhelmed bald assertions. Presidential tweets, however provocative, eventually disappear into the ether. Tuesday’s convictions could send two people who have had close relationships with Trump to prison, while one of them brought the investigation to the White House doorstep.

What took place Tuesday will ratchet up the pressure on the president, will embolden his critics, and will no doubt inflame and rally his supporters. If the past months have seemed increasingly hot, the coming months could be hotter still — there’s little doubt that the Trump presidency has now entered more treacherous territory, and no one can know where it will end.

Trump has tried everything to discredit Mueller’s now wide-ranging investigation. He has blasted it as a witch hunt, called the special counsel’s team thugs, sought to make the operation into a purely partisan exercise. He has complained that Mueller has strayed far from his original mandate to investigate Russian interference in the 2016 election. This month, the attacks escalated from volleys into a barrage, often multiple times a day.

On Tuesday, legal actions dropped with resounding force as a counter. By far the bigger blow for Trump came in New York, where Michael Cohen, his longtime former lawyer and fixer, pleaded guilty to tax fraud and campaign finance violations, including trying to buy the silence of two women whose stories he feared could influence the 2016 election.

In that plea, Cohen implicated Trump in the campaign finance violation, saying he acted at the direction of a federal candidate — namely Trump. What evidence exists to corroborate Cohen’s statement will await future legal developments and the public relations war that will ­intensify.

In Virginia, Paul Manafort, the president’s onetime campaign chairman, was convicted on eight counts of tax evasion and bank fraud. A mistrial was declared on 10 other counts. None of the criminal activity related to Trump’s 2016 campaign, but the convictions robbed the president and his team of any hope that the jury in Virginia would deliver a setback to Mueller’s team. Instead, it did the opposite.

Tuesday’s legal thunderclaps laid bare the vulnerability now facing the president. He and his lawyer, former New York Mayor Rudy Giuliani, have waged a relentless public relations war against Mueller, while fencing over whether Trump would agree to speak with Mueller’s prosecutors about his knowledge of the events under investigation.

Giuliani has been no help to the president. Either by ignorance or design, he has tried so many lines of attack against the Mueller team that he has ended up contradicting himself, misstating the facts and been forced to explain away statements such as the one he made Sunday on NBC’s “Meet the Press” that “truth is not truth.”

Mueller’s team has continued its methodical pursuit of what constitutes that truth to the best of anyone’s ability to find it.