Think of it this way: if Donald Trump is impeached – or resigns à la Richard Nixon – the new US president will be Mike Pence. And what is likely to be Pence's first decision? To pardon Donald Trump, à la Gerald Ford.
Now ask yourself this: what is Donald Trump’s number one priority as his former comrades and consiglieri turn against him, one by one, to save their own skins?
To stay out of jail. And – if possible – to ensure that his son Donald jr stays out of jail as well. (I’m not sure he’s that bothered about his son-in-law, Jared Kushner.)
Second question: if you are a US Democrat – or indeed a Republican who cares about the future health of the US political system – what is your number one priority? To get Trump out of the White House and bring him to justice for his myriad alleged crimes.
In which case, choose from one of the following two options: (A) impeach Trump and see him pardoned by Pence; or (B) defeat him in 2020 and see him prosecuted in the criminal courts. With a Democrat in the White House, there’ll be no pardons on offer.
So here’s the thing. The likelihood of the House of Representatives voting to impeach Trump and then the Senate voting by a two-thirds majority to convict him, which is what would be required to remove him from office, is close to zero. (Only twice in US history has the House of Representatives voted to impeach a president – Andrew Johnson in 1868 and Bill Clinton in 1998 – and in both cases the Senate voted to acquit. Nixon resigned before he was impeached.)
If the Democrats move to impeach Trump, and their attempt fails, he is likely to emerge from the process stronger, not weaker. Remember, Clinton’s poll ratings reached record levels after the failed Republican attempt to remove him.
What’s more, Trump’s thirst for revenge will be fearsome. As will that of his supporters.
Far better, I would suggest, for the Democrats to put all their efforts into defeating Trump in 2020. It means crafting a message to appeal to Trump voters in the all-important swing states, as well as determined work on voter registration in states where the Republicans have been trying to disenfranchise vast numbers of likely Democrat voters.
It also means, above all, finding a Presidential candidate who can do what Hillary Clinton failed to do in 2016: capture voters’ imagination, offer a vision for a better future, and represent the aspirations of ordinary, middle class Americans.
Someone perhaps from a Latino or other minority background, to push back against the ugly white supremacism that has characterised the Trump presidency; under the age of forty-five, to be able to talk plausibly about new ideas – oh yes, and please, at last, a woman.
If the Democrats really fail to beat Trump for a second time, they will have forfeited the right to be considered a serious political party. They know the stakes are high; they must not fail.