The court of impeachment in the United States Senate was adjourned by Chief Justice John Roberts “sine die” – without any future date being designated – but the court of public opinion about whether President Donald Trump is fit to continue in office is still in session, and the verdict of the American people will be rendered in November.

This impeachment of Trump by Democrats in the House of Representatives for the Ukraine affair was ultimately an imperative. After a whistleblower brought attention to a call between Trump and Ukraine’s President Volodymyr Zelensky, in which the US leader asked for Ukraine to investigate Joe Biden, then his chief political rival for 2020, the House of Representatives established a case that reached to the heart of the founding principles of the country, so that even Mitt Romney, the Republican nominee for president only eight years ago, could conclude:

“What he did was not 'perfect' – no, it was a flagrant assault on our electoral rights, our national security interests, and our fundamental values. Corrupting an election to keep oneself in office is perhaps the most abusive and destructive violation of one’s oath of office that I can imagine.”

Trump has never conceded a thing. It was always a “perfect” call. Yet even some Republican senators concluded that Trump committed a serious error – but that this did not rise to a “high crime” worthy of impeachment, and with the election coming in November, the people should be the ultimate judges.

Trump’s standing would be higher if he had emulated former president Bill Clinton, who apologised after being acquitted by the Senate: “I want to say again to the American people how profoundly sorry I am for what I said and did to trigger these events and the great burden they have imposed on the Congress and on the American people … This can be, and this must be, a time of reconciliation and renewal for America.”

Even some Republican senators concluded that Trump committed a serious error – but that this did not rise to a “high crime” worthy of impeachment, and with the election coming in November, the people should be the ultimate judges.

This is not in Trump’s playbook, as he made clear on Thursday from the White House: “It was evil. It was corrupt. It was dirty cops. It was leakers and liars … This is a political thing. We were treated unbelievably unfairly … It was all bullshit. But I’ve beaten them all my life, and I’ll beat them again if I have to.”

With the tailwind of contrition, Clinton’s personal approval rating rose to the 70s. Trump scorches the earth and enjoys peak approval, for him – but it is only at 49 per cent.

We will only know on November 4, the day after the election, if impeachment truly backfired on the Democrats: do they lose the House, Republicans keep the Senate, and is Trump still President?

All this unfolds when it is clear that Trump is vulnerable, despite his highly potent State of the Union address and his claim, with a strong economy and employment and relentless prosecution of his America First agenda, that: “The state of our Union is stronger than ever before.” His base fervently believes it.

Polling was consistent throughout impeachment that 50 per cent of voters want Trump removed from office. Senators who voted for impeachment received 12 million more votes in their states than senators who backed Trump.

But can the Democrats find a powerful nominee who can capitalise on the mood that Trump is unfit for office, that the country under his leadership is on the wrong course at home and abroad, and who can bring their party and the country together again?

Danger signs are flashing from the still-unsettled results in Iowa. Bernie Sanders, a Democratic Socialist, is clearly in a strong position, while the hero of the centre, former vice-president Biden, is in danger of collapsing.

But can the Democrats find a powerful nominee who can capitalise on the mood that Trump is unfit for office, that the country under his leadership is on the wrong course at home and abroad, and who can bring their party and the country together again?

Can Pete Buttigieg build on his Iowa breakthrough, capture New Hampshire next week and be the Jimmy Carter of 2020? In 1976, Carter, the cleanskin, anti-corruption, anti-Richard Nixon reformer and governor from a small state, came out of nowhere to win Iowa and ultimately the presidency. Can Buttigieg really put together the Obama coalition that beat John McCain and Mitt Romney?

If the two remaining women in the race, Elizabeth Warren and Amy Klobuchar, fail, the political party that supposedly reflects America’s diversity will have a white man as the nominee. Will women, African Americans, Hispanic Americans and others of colour really come out to vote.

If they go with Sanders – well, Trump will have his Clint Eastwood moment and have his day made and beat the Democratic communists to death. And win the House back and keep the Senate.

Is the party and country really to be saved by another white male New York billionaire in his late 70s – this time Michael Bloomberg?

There is a parallel warning sign from Iowa. Turnout was low: 170,000 Democrats attended the caucuses compared with 240,000 in 2008 when Obama surprised Hillary Clinton. Political scientists such as Rachel Bitecofer are concluding that elections are won by turnout, especially when voters are in hardened partisan silos.

A majority in America wants impeachment fulfilled and Trump out of office. The seminal political question of 2020 is whether the Democrats can crystallise that sentiment with their nominee, and win. The prospects are in doubt.