In my old job at the US State Department, colleagues often asked me what was likely to happen in this or that situation. Often, there was no way of knowing, and I reminded questioners that I was the director of policy planning, not of predicting. That said, prediction can be a useful intellectual exercise that serves us well in the new year.

The US presidential election in November is almost certain to be 2024’s most significant event. Of course, US elections are always consequential given America’s power and influence. But what makes this election fundamentally different is that it’s likely to be one in which the differences between the major party candidates far outweigh their similarities. Assuming President Joe Biden and former President Donald Trump gain their respective parties’ nominations, who wins will matter a great deal, both to the United States and to the world.

To be sure, there are some similarities between Biden and Trump. Neither believes in free trade, although Trump, unlike Biden, is an outright protectionist. Both favour a bigger role for government in the economy. Both wanted to exit Afghanistan. They also agree on the need to take a tough line towards China, especially when it comes to trade and investment in critical technologies.

But the differences are far greater. Biden is a career politician who believes in democracy, embraces its norms and is ready to work across party lines to forge compromises that benefit the country. Trump is an outsider who is fiercely partisan and rejects political norms (such as accepting electoral defeat), often putting himself before the country’s democracy.

Biden’s foreign-policy approach is centred around America’s allies, which he views as a great source of comparative advantage to the US. Trump regards allies more as economic competitors and a drain on America’s treasury. Whereas Biden has cast this period of history as a contest between democracy and autocracy, and argued that America needs to help democratic friends around the world, Trump gets along far better with autocrats and seems to envy their political control. The list of issues on which the two differ significantly is long, and includes climate change, immigration policy and access to abortion, to name a few.

As of this writing, Trump must be viewed as the favourite. His politics and persona are a better match for this populist era. Biden is also weighed down by the perception that he’s too old, and by inflation and an unpopular influx of migrants. The biggest question hovering over Trump is the extent to which his legal problems will translate into political problems.

But Americans won’t just be voting for a president; their ballots will also decide whether Congress will be controlled by the same party. For now, the upper chamber, the Senate, is in the hands of Democrats, while the House of Representatives has a Republican majority. The opposite is likely to be the case after November.

If Trump wins, a Democrat-controlled House might be the most significant limit on his power at the federal level, unless the Supreme Court shows itself to be more conservative than ideological. If Biden wins, a Republican-controlled Senate could make governing very tough.

Beyond the US, dozens of elections are scheduled to be held around the world in 2024. The first big one will take place in Taiwan on 13 January. Polls suggest a close race, with the ruling Democratic Progressive Party’s presidential candidate, William Lai, slightly ahead in a three-way race. But what matters most is that none of the candidates seems eager to do something reckless like declare independence. Still, if Lai becomes Taiwan’s next president, China would likely respond by increasing its military, economic and political coercion of the island.

Two months later, Russia, too, will hold a presidential election. There may well be no easier prediction than that Vladimir Putin will win another term.

Another easy prediction is that Mexico’s next president will be a woman after voters go to the polls in June. The two leading candidates are women, left-leaning and running on platforms that would continue many of the policies of the outgoing president, Andrés Manuel López Obrador.

The next 12 months will also be defined in no small part by the war between Russia and Ukraine. The third year of the conflict is unlikely to be decisive. Neither side can impose its will on the battlefield, and neither is inclined to negotiate.

Ukraine isn’t prepared to accept anything less than the full restoration of its 1991 borders. It may, however, be forced to adopt a more defensive strategy as Western military support is reduced. Putin appears confident that time will weaken the resolve of Ukraine’s supporters in the West. In particular, Putin is waiting to see if Trump wins, in which case he anticipates, with good reason, that US military and economic aid to Ukraine would decline precipitously, if not stop completely.

Then there’s the war between Israel and Hamas, now in its third month. At some point, the intensity of the war will fade somewhat and give way to an Israeli occupation of Gaza punctuated by periodic violence.

What follows in Gaza and in the occupied West Bank will be determined in large part by an Israeli election that will almost certainly be held this year. If Prime Minister Benjamin Netanyahu and a like-minded government continue in power, prospects for diplomacy will be bleak. The election of a more centrist government, however, would create diplomatic possibilities for the US and its Arab partners, though any diplomatic prospects could be jeopardised by a widening of the war to Lebanon or even Iran.

As for China and US–China relations, 2024 is unlikely to be a year of dramatic change. Chinese officials are for the most part focused on the economy and not looking for a confrontation with the US that could lead to more export controls and investment restrictions. Like Russia, China will have one eye focused on US politics, although many in China are less confident that a Trump victory would necessarily be in China’s interest.

The biggest event occurring in the wake of the US election is likely to be the annual United Nations Climate Change Conference (COP29), which will take place in November in Azerbaijan. It is equally likely that the gathering won’t produce results that meaningfully stem the crisis.

Last but not least is Argentina, where a new president campaigned on a platform of radical change. History suggests that when outsiders become insiders, reality often moderates what they do. Of course, Trump provides evidence that this is not always so. Such wrinkles are one reason why these predictions are so difficult.