The trial of 11 people charged with the murder of dissident Saudi journalist Jamal Khashoggi opened and was quickly adjourned in Riyadh last week. It may be that the outcome is fixed in advance. Yet that the hearing took place at all could be seen as progress of a kind. It suggests even a state as autocratic, inward-looking and undemocratic as Saudi Arabia is not immune to international opinion and can be forced, in extremis, to respect the human right to justice.

The Khashoggi affair has provided a chastening lesson for Mohammed bin Salman, the Saudi crown prince, who is widely believed to have ordered the journalist’s slaying in Istanbul in October. Until then, Salman was riding high, courted by Donald Trump, lauded at home for modest social reform and feared, if not respected, across the Arab Middle East for his war of attrition in Yemen and determination to face down Iran.

Salman’s subsequent fall from grace was swift. His reversal of fortune confounded the accepted narrative of an inexorable, global rise of like-minded, authoritarian “strongman” figures, riding waves of reviving nationalism and intolerant, rightwing populist and unilateralist sentiment. Yet there were signs elsewhere, too, that this toxic surge may be nearing its high point.

While the evidence for this incipient shift can be exaggerated, the extreme political trajectories that sent some governments and leaders veering off wildly into the far-right blue yonder from 2016 to 2018 may be beginning to self-correct. In other words, the wheel is turning and a more traditional, moderating left-right cycle could reassert itself. A critical turning point approaches, at which the conduct of global affairs may begin to “normalise” – or will become yet more dangerous and chaotic.

Viktor Orbán, long viewed as the standard bearer of anti-migrant, anti-EU, nationalist revanchism in Europe, is a case in point. Hungary’s prime minister remains firmly in control at home – for now. But his hard-right policies, particularly a so-called “slave law” undermining workers’ rights, are increasingly under attack. Last month saw large street protests in Budapest in support of opposition demands for the law’s repeal and the restoration of an independent judiciary and media.

The enduring Europe-wide appeal of Orbán’s ideas, and those of kindred rightwing populists in Germany, Italy and France, faces a crucial test in May, when a new EU parliament will be elected. Denmark, Poland, Portugal and Greece will also hold national polls this year. Predictions of additional successes for populist parties appear to be supported by the most recent Eurobarometer survey. Overall, only 42% of Europeans trust the EU, and even fewer (35% on average) trust their national governments.

But this level of voter alienation is nothing new and may actually be decreasing, according to the survey. Britain’s Brexit trauma appears to have had a cautionary effect, with fewer Europeans than previously favouring similar national action. Mainstream voters may also be more conscious that far-right politicians, even when they gain decisive power as in Italy last year, do not have better answers to their problems – and may make matters worse.

Kickback against overly authoritarian or anti-democratic leaders is more problematic in states suffering extreme forms of “strongman” governance, such as Egypt under Abdel Fatah al-Sisi. Sisi won a rigged presidential election last year, and there is talk of abolishing term limits so he can remain in office indefinitely. But many Egyptians have other ideas, as a predecessor, Hosni Mubarak, discovered to his cost. Rule by fear, aggravated by utter incompetence, can only last so long.

Similar considerations apply to Recep Tayyip Erdoğan in Turkey, who finally succeeded last year in taking all the reins of power. Now the blame for numerous national problems – the economy, security, corruption, censorship, abuse of power – lies with him. Meanwhile, hundreds of thousands of Turks are voting with their feet, taking talents, money and businesses abroad. It’s clear that in Erdoğan’s boundless hubris lie the seeds of his destruction. Downfall could come sooner rather than later.

This theory of nationalist strongmen fatally faltering may also be applied to India’s Narendra Modi, who faces a tough re-election challenge this year, and even to China’s formidable Xi Jinping, who promised a better life for all and now appears clueless in the face of an economic slowdown. And there’s Trump, the ultimate strongman wannabe, who clearly believes he is entitled to do anything he wants, including building a wall with Mexico, but is slowly and painfully discovering he is not.

How Trump reacts to tougher Congressional resistance and deepening legal entanglements is the story of the next two years. He may play it by the constitutional book, but that seems unlikely.

If, like failing authoritarian leaders everywhere, he tries instead to impose his will by any available means – such as declaring a bogus “national emergency” – the resulting domestic and global disruption will be severe.