President Donald Trump‘s long-serving personal lawyer, Michael Cohen, pleaded guilty to twin federal election law offences directly implicating the President. Mr Cohen’s statements set the foundation for the United States Attorney for the Southern District of New York to subpoena Mr Trump to testify about $280,000 paid to a adult film star (Stormy Daniels) and a Playboy model (Karen McDougal) during his 2016 campaign for their silence about his decade-old affairs with each to influence the outcome of the election. The disclosures could have alienated his religious right-wing supporters.

Mr Trump is likely to resist the subpoena. That would force a challenge in the United States Supreme Court as to whether a sitting president is accountable to the criminal law, as are all other officers of the United States, including members of Congress and justices of the Supreme Court. The controlling precedents are against President Trump. In United States v Nixon, the Supreme Court unanimously compelled President Richard Nixon to surrender presidential tapes and documents for use in a criminal trial against his top assistants. None of Mr Nixon’s four Supreme Court appointees voted in his favour. In Clinton v Jones, the Court held that President Bill Clinton could be compelled to testify in a civil suit bright by Paula Jones alleging sexual harassment. Neither of Mr Clinton’s two appointees voted in his favour. Mr Trump is similarly unlikely to win the votes of Justice Neil Gorsuch, whom he appointed, or Brett Kavanaugh, whose nomination will soon be confirmed. They would strain to avoid an appearance of bowing to their benefactor as did the Nixon and Clinton justices.

An adverse ruling by the Supreme Court would end the Trump presidency. If he defied the Supreme Court’s order, he would be immediately be impeached by the House for subverting the Constitution’s separation of powers, convicted in the Senate by a two-thirds majority, and removed from office. (Attempts to subvert the Constitution are made impeachable offences, ie, high crimes and misdemeanours, under Article II, section 4). The Supreme Court remains the nation’s most venerated and untarnished civil institution. Any attack on a decision joined by Trump’s own appointees would ring hollow.

President Trump would be equally doomed if he agreed to give testimony under oath. In his mental universe, he does not distinguish between truth and falsehood. Perjury would be inescapable. He has already lied repeatedly about pay-offs to the two women. His foremost lawyer and spokesman, Rudy Giuliani, has insisted “truth isn’t truth” in explaining why Trump’s testimony would inexorably prove perjurious. Perjury is an impeachable offence, and occasioned President Clinton’s impeachment by the House of Representatives.

President Trump may also be implicated in a June 2016 meeting in Trump Tower between Donald Trump Jr, Paul Manafort, and Jared Kushner on the one hand, and agents of Russian President Vladimir Putin on the other hand. The purpose, according to Donald Trump Jr, was to solicit or receive damaging information on Democratic Party nominee Hillary Clinton to use in the election campaign. Federal law prohibits soliciting anything of value from a foreign government or agent to influence the outcome of an election even if the solicitation fails. It seems implausible that President Trump was clueless about a meeting of such electoral importance. That conclusion is reinforced by his concoction with Donald Trump Jr of a false story that the President Putin’s minions were embraced to discuss adoptions of Russian children – a non-issue in the 2016 presidential campaign

Paul Manafort, President Trump’s former campaign manager, was found guilty of eight counts of tax and bank fraud involving huge sums concurrently with Mr Cohen’s guilty plea. The convictions discredit Mr Trump’s soundtrack that special counsel Robert Mueller is engaged in a political witch-hunt with no legal justification. Indeed, Mr Mueller has indicted or convicted more than 30 persons or entities.

The Manafort convictions combined with Mr. Cohen’s guilty plea and the guilty plea of Mr Trump’s former national security adviser, Michael Flynn, puncture Mr Trump’s campaign pledge to “drain the swamp”. The president’s popularity is dwindling, which will spike the probability of impeachment.

It blends law and politics. Members of Congress respond to public opinion. If it turns against President Trump because of the epidemic of lawlessness in and around the White House, members will be emboldened to initiate impeachment hearings, especially if control of either the House or the Senate flips to the Democrats after the November 2018 elections. President Nixon’s public approval rating had plunged to 22 percent when he resigned in 1974 after the House Judiciary Committee voted three articles of impeachment. When President Trump’s political barometer falls to that level, his impeachment and conviction are a certainty.

President Trump epitomises narcissism. He has scorned the adage that he who loves himself will have no rivals. He has virtually no personal friends in Congress willing to fall on a sword for him. Indeed, most members would prefer Vice President Mike Pence in the Oval Office to Mr Trump. Mr Pence echoes the same general policies, but without the vulgarity and venom of Mr Trump.

Mr Manafort has become a wild card for President Trump after his tax and bank fraud convictions. Even if he resists cooperation with special counsel Mueller, Manafort can be compelled to testify with a grant of immunity about the June 2016 Trump Tower meeting with Russian officials when he was Trump’s campaign manager to solicit “dirt” on Clinton. Mueller can afford to grant immunity. He does not need additional convictions to dispatch Mr Manafort to prison for long years or life.

According to a recent book by Mike Isikoff and David Corn, Russian Roulette, Mr Manafort and Donald Trump Jr both solicited the Russians for derogatory information – a clear violation of the anti-solicitation prohibition in federal campaign finance laws as applied to foreign nations or agents. With a grant of immunity, Mr Manafort would be compelled to reveal everything that transpired and what President Trump knew before and after. That Manafort testimony could implicate Mr Trump in a conspiracy to violate the law against foreign contributions to political campaigns. Mr Mueller would then subpoena Mr Trump for testimony about the apparent “Russian collusion”. That would end Trump’s presidency. He is a compulsive liar and would commit perjury as Mr Giuliani has acknowledged.

The imponderables that will determine how quickly the Doomsday Clock for the Trump presidency strikes midnight are threefold: the credibility of Mr Cohen as a witness under klieg lights; the speed with which Congress begins televised hearings into President Trump’s wrongdoing; and, the timing of subpoenas for Mr Trump’s testimony from the US Attorney for the Southern District of New York and special counsel Mueller.

President Trump’s ouster from the White House is no longer a question of if but when.

The views expressed in this article are the author’s own and do not necessarily reflect Al Jazeera’s editorial stance.