When the history of our time is written, the year 2019 may stand as the turning point in the battle for liberal democracy — a year when millions of people rose to fight against the forces that for more than a decade have been bulldozing it, trampling the values of free societies almost unimpeded.

The Arab Spring uprisings that began the decade, starting in Tunisia in December 2010, seemed to augur a new flourishing of freedom. Most of those rebellions soured, and since then we’ve watched the forces of authoritarianism stage an aggressive comeback.

Leaders such as Vladimir Putin, Xi Jinping, Abdel Fatah el-Sissi and Recep Tayyip Erdogan cemented their power and inspired imitators around the world. In 2019, we have finally seen protesters, voters and activists reassert their belief in democratic ideals. The results in most places remain inconclusive. But the battle has been joined, from the United States to Eastern Europe, from Africa to Asia and Latin America.

The pivotal contest is taking place in the United States, the country whose deep democratic roots make it well-equipped to defy the authoritarian trend. The United States remains a vigorous democracy, but it, too, is one of the nations where democracy, according to Freedom House, “has weakened significantly”, thanks in part to a president who launches incessant attacks “on the rule of law, fact-based journalism, and other principles and norms of democracy”.

This year, that president, Donald Trump, was impeached in an historic vote. Although the chance that legislators will remove him from office remains almost nonexistent, impeachment signalled that many Americans strongly reject his assault on democratic norms. The 2020 election will determine whether the nation that has been an icon of global freedom will shift to a democratic path or continue on the rutted road to authoritarianism, which would have ominous implications for freedom around the world.

The fight was also joined in Eastern Europe, whose people emerged from behind the Iron Curtain to embrace democracy in the late 1980s and early 1990s — only to fall under the spell of autocratic leaders over the past decade. The combination of mass migration and an economic crisis opened the door to demagogues, who have undercut the independence of the judiciary, promoted majoritarian policies and destroyed the independent media.

In 2019, however, populist nationalists who had known few defeats at the polls suffered shocking losses in big cities. City mayors don’t usually form international political alliances, but in December, the mayors of Warsaw, Budapest, Prague and Bratislava announced the Free Cities Alliance, which aims to protect and promote “our common values of freedom, human dignity, democracy, equality, rule of law, social justice, tolerance and cultural diversity”.

If there was one clear victory for democracy, it came in the most unlikely place: Sudan. Demonstrators in a country that had been ruled for three decades by a serial committer of genocide, incredibly managed to topple Omar Hassan al-Bashir. The country faces innumerable challenges, but Bashir sits in prison and sceptics about the success of the protests have so far been proved wrong.

In Algeria, demonstrators unseated another seemingly immoveable leader. The infirmed president Abdelaziz Bouteflika, who had remained in office for 20 years even after becoming so ill that it was doubtful he governed, was set to run yet again for re-election.

The protests managed to persuade what Algerians call le pouvoir — the power — to bring an end to Bouteflika’s career. But protests continued this month after the election winner was declared. Bouteflika’s successor, Abdelmadjid Tebboune, 74, is close to the military. Making the future more uncertain, General Ahmed Gaid Salah, the powerful military chief, died on Monday.

Advocates of democracy fearlessly rejected China’s curtailment of the freedoms it had promised Hong Kong. For months, protesters there have been challenging Beijing and its puppet regime in Hong Kong, even as China issued intimidating warnings.

In Lebanon and Iraq, demonstrators demanded an end to the sectarian arrangements that have turned governments into candy stores for corrupt politicians, condemning the public to enduring bad governance as the powerful plundered the state.

In India, moves by Prime Minister Narendra Modi to disenfranchise India’s Muslims met with a furious response — not only from Muslims themselves, but also from defenders of a secular, democratic India that is a home to all its people.

In Latin America, demonstrators poured into the streets to demand accountability in country after country. In Bolivia, most notably, they managed to remove President Evo Morales. The move was viewed as a coup by some and as a victory for democracy by others. Morales had overstayed his welcome, running for a fourth consecutive term even after Bolivians voted no in a referendum over allowing him yet another term.

Election monitors said he cheated in the October election. The military ushered him out amid mass protests. The real answer to what occurred — democracy or coup — will come when we see whether the interim government holds free elections.

Whether or not history determines that 2019 was the year when the people started to turn the tide against autocratic nationalists will be known only in retrospect.

The forces of democracy joined the battle with ferocity. The outcome of their efforts will become evident in 2020, in what will be the central contest of our time.

• Frida Ghitis is a former CNN producer and correspondent who writes about world affairs for The Washington Post, CNN.com and World Politics Review