The fallout from some of this year’s most divisive elections is likely to become fully apparent only later in the new year. In the United States, triumphant congressional Democrats will try to rein in President Trump, but it remains to be seen how far they are willing, or even able, to go.

In Congo, voters headed to the polls in historic elections on Sunday, even as allegations of voter fraud mounted. Human rights critics made similar accusations at almost the same time in Bangladesh, where elections were held last weekend, too. Final analyses of both votes — and whether they violated voters' rights — won’t be in until the new year.

Across the world in 2018, voters heard many of the same arguments: The establishment has failed you; corruption is rife; immigrants are harming our country; your way of life is under attack.

In some places, it was a winning strategy. Italian and Pakistani voters brought once-fringe anti-establishment parties to power. Swedes and Bavarians gave traditional parties some of their worst results.

In other countries, there was a backlash. Malaysians dumped their prime minister despite his appeals to sectarianism. Americans gave Democrats huge gains in the House of Representatives, spurning Republican appeals on illegal immigration.

Here is a recap of some of the key votes around the world this year:

Italy (March 4)

The first major European election in 2018 set the tone for the rest of the year: Italian voters abandoned establishment parties in droves, choosing to back newer, more populist alternatives instead. The upstart Five Star Movement (M5S), a party formed less than a decade ago by a comedian, was the overwhelming winner of the popular vote.

After months of negotiations, M5S agreed to form a coalition government with the far-right League party. The two parties have set Italy on a collision course with the European Union, but the returns have not been good so far. Italy’s recently proposed budget, for example, would have caused such a large deficit that the E.U. took the rare step of vetoing it. Rather than fighting tooth and nail for its spending plans, Rome now appears ready to back down.

Malaysia (May 9)

According to his critics, Prime Minister Najib Razak intimidated opponents, stirred up religious tensions and manipulated votes in the hope of winning a third term in office. None of it mattered. With Najib suspected of embezzling hundreds of millions of dollars from a state investment fund, voters tossed him out in favor of 92-year-old Mahathir Mohamad, a former prime minister and ex-mentor of Najib.

As my colleagues wrote in May, Najib’s ouster was “rare good news for supporters of liberal democracy elsewhere around Southeast Asia, a region that has mostly been lurching toward autocracy, violence and religious fundamentalism in recent years.” Malaysia has since repealed a restrictive “fake news” law passed by Najib, who himself has been charged with corruption.

“This shows that the pendulum can swing back from authoritarianism,” Bridget Welsh, a professor of political science and Malaysia specialist at John Cabot University in Italy, told my colleagues.

Turkey (June 24)

Authoritarianism struck back the following month, when Turkish President Recep Tayyip Erdogan was elected to another term. In the months before the vote, Erdogan’s long-running grip on power seemed more fragile than ever. Turkey was in the middle of an economic crisis, and the country’s opposition, fed up with the purges and repression that have followed a failed 2016 coup, was unusually united.

But Erdogan emerged with yet another victory — with the help, critics charged, of possible voter fraud and other intimidation techniques. His Justice and Development Party also stayed in power, forming a coalition government with the right-wing Nationalist Movement Party.

“Erdogan is no longer the pioneering politician who shook up Turkey’s sclerotic economy and delivered greater freedoms to once-marginalized pious Muslims,” wrote my colleague Ishaan Tharoor. “Instead, he’s becoming an era-defining strongman and a cautionary tale to democrats elsewhere.”

Those strongmen tactics could also serve as a lesson to two new South American leaders who won elections this year. Brazil’s president-elect, Jair Bolsonaro, and Mexico’s new president, Andrés Manuel López Obrador, have little common ground in terms of their policies: Bolsonaro is right-wing while Obrador campaigned on a left-wing agenda. But both leaders have already been compared to President Trump for their populist tones. The three leaders also share another similarity: All of them were considered political outsiders before their victories.

Pakistan (July 25)

This may sound like a familiar story: A playboy celebrity reinvents himself as an anti-establishment firebrand and rises to become the leader of a nation. That’s what happened in Pakistan this year when former cricket star Imran Khan led his Pakistan Movement for Justice party to victory in a general election.

Khan, now Pakistan’s prime minister, followed a familiar nationalist script. He charged that the country’s elites were out of touch and endemically corrupt and said that liberals were “thirsty for blood.” He alone could clean up the country and make it safe for the pious and upstanding masses.

At the same time, he appeared to get a decisive boost from Pakistan’s powerful military. Human-rights activists said the military, which has frequently intervened in the country’s democracy, intimidated opponents, cracked down on media and helped engineer the prosecution of Khan’s chief rival, former prime minister Nawaz Sharif, on corruption charges.

Sweden (Sept. 9)

Scandinavia is often held up as a model of stability and consensus, but parliamentary elections in Sweden in September proved that virtually no country in Europe is immune to the anti-establishment surge of the past two years.

Like their counterparts in Italy, France, Germany and other countries across the continent, Swedish voters dealt major blows to establishment parties near the center. The center-left Social Democrats had their worst showing in more than a century, and the center-right Moderates also lost a significant chunk of seats. The right-wing, anti-immigration Sweden Democrats scored the biggest gains.

Nearly three months after the vote, Sweden’s parties are still trying to assemble a new government.

Cameroon (Oct. 7)

Paul Biya, who has been Cameroon’s president since 1982, won yet another term this year. While the outcome was never in serious doubt — “Cameroon is one of Africa’s most enduring electoral authoritarian regimes,” as a contributor to The Post’s Monkey Cage blog put it — the vote may turn out to be a prelude to a serious conflict between Cameroon’s French- and English-speaking populations.

Biya’s English-speaking critics have long complained that they are systematically marginalized by the country’s Francophone elite. The elections took place amid escalating tensions between the French-speaking government and its supporters and English-speaking separatists; several Anglophone protesters were killed both before and after the elections, and there is pressure on Biya to step down despite his victory.

More on WorldViews: