A protest that got out of hand? Carefully planned riot? Attempted putsch?

The political year began with an event that was surely all of these, as a mob of Donald Trump supporters stormed the U.S. Capitol building while U.S. lawmakers were debating Joe Biden’s presidential victory in the Electoral College.

In the end, the transition was orderly. Biden was inaugurated two weeks later, and Trump left office as the first U.S. president to be impeached twice. Yet the legacy of Jan. 6 is one of deep and persistent polarization.

Biden said the U.S. was “back” after the America First policies of the Trump era. Still, with domestic concerns front and center, it hasn’t always looked like that to the rest of the world. The chaotic pullout of American forces from Afghanistan without consulting U.S. partners in the two-decade war was a case in point.

Read more from Bloomberg’s year in climate, economic recovery, crypto, Covid-19 and supply shortages.

The Biden administration’s most consequential foreign-policy decision, however, was to lean into its standoff with China and square up for an epoch-defining rivalry that will affect us all. Washington marshaled like-minded allies as it sought to challenge Beijing on its human rights record and check its access to technologies including leading-edge semiconductors.

China focused on becoming more self-reliant and pursuing “common prosperity,” while cracking down on tech companies and tightening its control over Hong Kong. President Xi Jinping consolidated power ahead of a Communist Party plenum next year that could see him potentially rule for life.

A Xi-Biden virtual meeting and a bilateral climate deal at the COP26 summit in Scotland helped dial back the rhetoric, yet the situation remains volatile—nowhere more so than over Taiwan. China’s territorial claims and U.S. support for the democratic government in Taipei ensure that the island will be on the front line, a potential flashpoint of the great power tussle into 2022 and beyond.

There were also ominous developments for the global balance of power in the former Soviet Union. Russian President Vladimir Putin caused an international uproar by jailing opposition leader Alexey Navalny on his return to the country. A more recent concern is the Russian forces massing on Ukraine's border.

Europe will have to confront unfolding events without its de facto leader after Angela Merkel was replaced by Olaf Scholz following her almost 16 years as Germany’s chancellor.

While her departure has been long planned, it wasn’t that way for other leaders. In Japan, the curse of short-lived premierships struck again, with Fumio Kishida next to step up. The laws of political gravity finally caught up with Benjamin Netanyahu after 15 years as Israel’s prime minister, while archenemy Iran elected a new president ahead of negotiations aimed at resuming the nuclear deal abandoned by Trump.

Covid-19, of course, continued to upend politics and wrong-foot political leaders. Justin Trudeau misjudged Canadian voters by calling a snap election on the back of his pandemic handling—only to fall short of a majority. U.K. Prime Minister Boris Johnson, who presided over one of the worst death tolls in Europe, continued his political high-wire act as Brexit became real and Britain’s supermarket shelves emptied.

Riots in South Africa fueled by economic injustice and frustration at lockdowns left more than 350 dead, even before the country rang the alarm over a new Covid variant. Elsewhere in Africa, Prime Minister Abiy Ahmed of Ethiopia ended the year fighting rebel forces two years after he received the Nobel Peace Prize.

In Latin America, too, the pandemic exposed inequalities that brought electoral surprises in Peru and Chile. Regional heavyweight Brazil faces a no-holds-barred contest for the presidency next year.

Biden, meanwhile, ended a stumbling first year with the passage of his massive spending program after extensive wrangling. It’s a success he’ll need to sustain him into 2022 as the relentless U.S. electoral cycle gears up for midterms.