The unpleasant problem for all those strident anti-Trump protesters in the US holding up their “NOT MY PRESIDENT” placards is that he is, whether they like it or not.

That one slogan reflects the underlying personal vanity of the era: Democrats seem to be taking Trump’s elevation to the White House as a personal affront more than a political outrage to the nation.

So the internet buzzes with clever memes and mash-ups poking fun at the teeming stupidities of the new President. Fresh satirical blood runs in the veins of Saturday Night Live as it lampoons Trump and his stumblebum crew of insiders.

This is all very amusing, but it is preaching to the converted.

Look how intelligent, whimsical and cultured we are (goes the unspoken message), compared with those deplorable rednecks who voted for him! Worse than its smug superiority, this retreat into mockery allows the anti-Trump brigade to absolve themselves from the discomforts and difficulties of committing to any practical response.

There’s also a subtle hypocrisy behind the rage of the American urban liberals. Trump is the outcome of precisely the type of democracy they’ve supported for generations. It’s a bit late now to start railing against the same electoral system that gave them their beloved FDR, JFK and Barack Obama.

Surely the real issue — for those with the will to confront the hard politics of this crisis — is how to deal with the excesses of The Donald, and ultimately defeat him. In that context, the lessons of recent history are, as ever, instructive.

[Razer: white guilt and the individualised impotence of modern protest]

We know that ridicule and contempt alone won’t do the job. The White House has always commanded so much power that the presidency itself is armour-plated. Nor is the authority of that office qualified by the precedents and conventions we accept as central to our own Westminster system; presidents aren’t required to resign when caught out in a lie, or if their party loses a vote of confidence in the legislature.

Unseating a US president is therefore a long, exhausting process that requires sustained effort by people of both principle and courage.

Lyndon Baines Johnson, the Texan Democrat who became president after the assassination of John F. Kennedy in late 1963, enjoyed huge popularity and was returned to the White House by a landslide the following year.

Yet, less than four years later, LBJ did so poorly in the New Hampshire primary that he declined to even seek his party’s nomination for the 1968 presidential race.

Johnson — despite an admirably progressive domestic legislative record — had made the fatal error of escalating US involvement in the Vietnam War.

Soon, many of LBJ’s own Democrat colleagues, including Robert Kennedy, were openly challenging his conduct of the conflict in Indochina. Casualties mounted, college students burned their draft cards, there were constant anti-war demonstrations in the streets. The bloody Tet Offensive of 1968 finally turned majority American sentiment against Johnson and the war.

Robust, unrelenting opposition from both the political and public wings had made an American president’s position untenable. It could be done.

And who did the land of the free then elect in his place? Richard Milhous Nixon.

The broad outline of the Watergate saga and how it brought down the president is familiar. Hollywood would have us believe that two young investigative newspaper reporters did the demolition job with the help of their undisclosed Washington source, “Deep Throat”.

Woodward and Bernstein certainly provided plenty of the initial ammunition, but Nixon was finally forced into resignation by the combined commitment to truth of some brave politicians and even braver judges and lawyers.

In the Senate, crusty old Sam Ervin chaired a select committee that patiently pursued Nixon’s tawdry collection of “operatives” and began assembling undeniable evidence of who ordered the burglary and its shoddy cover-up.

District Court judge John J. Sirica — a registered Republican who’d twice voted for Nixon — made the courageous ruling that the White House and the attorney-general had a case to answer, and that the damning Oval Office tapes must be heard.

It took three years, but, in the end, the president resigned before he could be impeached and 25 officials of the Nixon presidency, including four cabinet members, went to jail for their parts in the Watergate conspiracy.

[Rundle: trickle-down economics and the flood of disadvantage]

It could be done, and it was. Not by smart cartoons in The New Yorker or dinner party disdain, but through the patient, hard yakka of people who understood how the mechanisms of a corrupt regime worked, and how it could be dismantled.

Yesterday’s forced resignation of Trump’s freshly minted National Security Adviser, Michael Flynn, is a potent demonstration of that process.

Weeks ago, the Justice Department quietly warned the new administration of the contradictions between Flynn’s public statements and the details of the phone calls he’d made to Russian diplomats. The Washington Post then confirmed that Flynn had, indeed, had inappropriate discussions with the Russian ambassador. Bye, bye Mike!

The President’s credibility has taken its first hard knock, and there is no shortage of targets to choose from for another assault on the fantasy world of Donald Trump.

The conflicts of interest between his businesses and the presidency. His failure to release his tax returns. The anti-Muslim travel bans. His attacks on the judiciary. The murky relationship with Russia. There is plenty to examine beneath those rocks.

But one huge obstacle remains: Johnson and Nixon only quit when they were forced to accept they no longer had sufficient support from their own side on the Hill. Democrats in Congress and the Senate abandoned LBJ; Republicans could no longer tolerate “Tricky Dicky”.

Trump, however, sits on comfortable majorities in both houses while taunting the media and the conventional political class into dumbfounded disorder. It may be some time before a workable strategy to dislodge him emerges, but it can be done.