After Cohen's pleas and a guilty verdict, minutes later, in the bank and tax fraud case against Trump's former campaign chairman, Paul Manafort, Democrats wasted no time in demanding a congressional investigation into the Cohen affair and warned of an increasingly dangerous threat to the rule of law. Loading "This is getting deeper and deeper, and it's going to get more and more serious," said congressman Jerrold Nadler, the top Democrat on the House Judiciary Committee. Asked about the potential for an impeachment inquiry, Nadler said he wanted to see more evidence. "We need to see what Mueller comes up with," he said, referring to Robert Mueller, the special counsel investigating the Trump campaign's ties to Russia and whether Trump obstructed justice. "We may get there." Democrat senator Ron Wyden broached the charged phrase "high crimes and misdemeanours", the Constitution's threshold for impeachment.

But legislators in Trump's party, who have repeatedly brushed away concerns about Trump's own legal exposure, seemed unperturbed. With the House away from Washington for the month and senators sick of the drama emanating from Trump's orbit, few openly rose to Trump's defence. Those who did said the threat was elsewhere. "Campaign finance violations — I don't know what will come from that, but the thing that will hurt the President the most is if, in fact, his campaign did coordinate with a foreign government like Russia. Anything short of that is probably going to fall into partisan camps," Senator Lindsey Graham, a Republican, told reporters. As a House member, Graham helped prosecute the impeachment of president Bill Clinton two decades ago. Loading Senator John Cornyn, the No. 2 Senate Republican, repeatedly stepped around questions from reporters about the implications of Cohen's pleas. He observed instead that independent counsel investigations often tended to veer away from their origins. "I have no idea about what the facts are surrounding his guilty plea, other than the fact that none of it has anything to do with the Russia investigation," Cornyn said. "I would make the same observation with regard to Mr Manafort."

Aides to Republican Speaker Paul Ryan said he was "aware of Mr Cohen's guilty plea to these serious charges" but would wait for more information to comment further. Senator Mitch McConnell, a Republican and the Senate majority leader, said nothing publicly. In a sign of how cemented both the opposition to and support for Trump is a year-and-a-half into his presidency, few Republicans believed the double-digit felony count would drastically reshape the political climate. Party strategists largely dismissed Manafort's conviction, viewing it as not directly related to Trump, and said voters had already concluded that the President agreed to pay off the actress Stephanie Clifford, better known as Stormy Daniels. Loading "I'd be surprised if it causes anything more than a ripple in the campaign," said Steven Law, who oversees the Senate Leadership Fund, the "super PAC" aligned with McConnell. Part of what the President has going for him is that expectations about his conduct were already low before last week's split-screen drama, with Democrats believing he is an amoral demagogue and many Republicans seeing him as an unsavoury character who has the right policies and, just as importantly, the right enemies.

"In a normal world, it's not good," said Chris Wilson, a Republican pollster. "In today's political environment, it probably just creates further polarisation and political tribalism." This is not to say that the President's approval ratings will not dip slightly or that preferences for a Democratic-controlled Congress will not rise on the news: many Republicans believe they are already likely to lose control of the House and that such Trump-linked wrongdoing will only further enhance Democrats' chances for a takeover. But given the health of the economy and relative stability abroad, Trump's approval ratings are already significantly lower than what virtually any other president would be enjoying at this moment of his administration. And if there is one predictable element of this otherwise unpredictable presidency, it is that some new story will detonate in the days or weeks ahead, pushing the last eruption off the homepage and television screens. Loading Replay Replay video Play video Play video That fact was both a tonic to Republicans on Tuesday and a reason for concern. While suggesting that the Manafort and Cohen felonies were merely this week's version of the Omarosa tapes - the latest ephemeral drama to grip Washington but barely faze voters - Republican officials were also apprehensive about what more Cohen may reveal on his way to a likely prison sentence.

And even more worrisome to Republicans is what damage Trump may do to himself. If the President is seen as thwarting Mueller's investigation, either by terminating the special counsel or pardoning allies who are implicated, it would create a far more serious upheaval and force Republican legislators into a confrontation they have long avoided. "Of course you can imagine the President doing things that would be counterproductive," said Republican senator Bill Cassidy, before adding with evident hope in his voice: "But you also could imagine the President saying something but never acting on it, just venting." Privately, Democrats speculated that the guilty pleas and decisions stacking up around Trump would fuel a message that Republicans controlling all levers of Washington were woefully corrupt. Their case got another boost only hours later, when a federal grand jury indicted congressman Duncan Hunter of California on charges that he spent tens of thousands of dollars in campaign funds on personal expenses. Hunter was the second Republican congressman to be federally charged in just three weeks and, taken together with the Cohen and Manafort felonies, some Republicans thought the misdeeds carried a stench reminiscent of the 2006 elections, when Democrats last reclaimed control of Congress. "Today's events are a bombshell, and if nothing shakes them loose from their purposeful inertia, the electorate will do so," senator Richard Blumenthal, one of Trump's most outspoken Democratic critics, said of the Republicans.

New York Times