When prophecy fails, the prophets get creative. That was the lesson of Leon Festinger and his colleagues who, in their 1956 study of an American UFO cult, coined the term "cognitive dissonance" to describe how the cultists frantically rewrote their own beliefs after their predicted apocalypse failed to appear.
he inauguration of US President Joe Biden has set off a similar scramble for meaning. The Stop the Steal protesters behind the violence at the Capitol were certain that they would expose a massive election fraud and keep Trump in power. Many were adherents of the cult-like QAnon movement - which mixes evangelical Christianity with baroque conspiracy theories - who believed right up until last Wednesday that the "Satanist" Democrats were about to be liquidated in a military coup. Instead, like Lucifer and his angels in Paradise Lost, these extremist groups now find themselves cast out into a political netherworld: condemned by legislators, harried by law enforcement and exiled from mainstream social media.
On Friday, Biden ordered a probe into domestic terrorism, while the FBI has arrested more than 100 people and may charge some with sedition.
Yet as movement leaders scramble to explain their prophecy's failure, the future of American politics - and particularly the Republican Party, which has often embraced their ideas - may be shaped by what their followers do next.
"I think QAnon as a vessel will be significantly damaged by the anticlimax," says Liam Donovan, a Republican strategist and former Senate fundraiser. "But the isolation, frustration, and desperation it tapped into will find somewhere else to go."
On fringe social networks such as Telegram and Gab, pro-Trump extremists are sharply divided.
A flurry of new theories are competing to show how this month's events are all part of the plan, while some people struggle with doubts. "I want to believe you, but what we are seeing can't be fake," said one message seen by reporters.
Mike Rains, who helps run a support group for people whose loved ones have been sucked into QAnon, says many of its "rank and file" believers are furious at its "promoters".
"It will be harder to recruit, but the people in the movement now will be more extreme," says Rains.
The chaos is already being exploited by neo-Nazis and white supremacists, among whom Gab and Telegram are widely used. Monitoring the internet, it is not difficult to find many attempts at channelling despair into recruitment - with certain users pointedly blaming Israel or Jews and posting links to archives of racist texts. Not everyone is receptive: one Telegram group leader complained of newcomers spreading vicious anti-Semitism. Some were kicked out, with the leader saying, "this is not the Nazi group".
The bigger issue is what will happen to Trump's base, and to the Republicans. Those groups are hard to disentangle from QAnon and Stop the Steal because of how thoroughly Trump and leading members of the party have adopted their platforms.
"A Venn diagram of those three circles shows that the overlap is growing," says Doug Heye, a former communications director of the Republican National Committee. He recalls how conspiracy theories about Barack Obama's birth certificate began to spread through the party's voters in 2009 and 2010, and later served as a springboard for Trump's candidacy.
Donovan describes the former president as a man who "marinated in, ingratiated himself with" the Republican "fever swamp" - an "authentically conspiracy-minded" president who stoked these latent currents until they became inescapable. His prize was a fervent, energised and volatile support base - including first-time voters and former Democrats - which many Republicans still fear to cross.
Even after the Capitol riots, 140 Republicans in the House of Representatives voted not to certify Biden's victory, while 197 opposed Trump's impeachment. The House Republican leader reversed his claim that Trump was responsible for the violence. Loyalist RNC chairman Ronna McDaniel was re-elected. Two newly elected House members have declared support for QAnon.
Donovan argues that while QAnon and Stop the Steal's specific ideas may not last, they have revealed a deeper feeling that future politicians will seek to harness. "The energy within the party in recent years, and the impulse that propelled Trump himself, is anti-elite, anti-establishment, populist and grievance-minded. I don't expect that to change, and if anything it will become more powerful."
Much depends on Trump himself, whose social media posts delivered regular shots of adrenaline to extremists. Without that, insiders say the temperature in the party has already gone down. Yet the former president still commands enormous influence, and if he can find a new megaphone - or launch a party of his own - Republicans may be forced to dance to his tune again.
Telegraph Media Group Limited