Ten years ago, President Obama took the oath of office under what he warned were “gathering clouds and raging storms.” The nation faced a growing economic crisis, unending wars abroad and an uncertain future. The new president said his election showed that the nation had “chosen hope over fear, unity of purpose over conflict and discord.”

The decade since has proven Obama’s warnings more prescient than he could have known — but his optimism misplaced.

The intervening years will be remembered as a decade of decoupling, both in the United States and on the world stage, as generational, economic and racial strife rends the post-Cold War fabric of liberal democracy and an increasingly interconnected world. What once appeared to be a steady trend toward globalization and stability has become a nationalistic backlash of instability.

At home, the Teens opened with the Tea Party movement, a revolt against the Affordable Care Act that metastasized into a new strain of conservative populism among white working-class Americans who increasingly felt left behind. A decade of rapid change showed gains for a younger and more diverse generation and for minority groups that make up a greater share of the population.

“Polarization is everything this decade is about, and it may define the future as well,” said the demographer Cheryl Russell. “Polarization is occurring in every facet of American life.”

The great recession that hung over Obama’s inauguration became a decadelong recovery, but one so unevenly felt that it has fueled greater division between the winners and the losers.

The consolidation of American economic power has accrued almost entirely to the benefit of the largest metro areas in the country, the recovery’s clear winners.

In 2010, the 29 largest metropolitan areas accounted for half the nation’s gross domestic product; by 2017, the last year for which figures are available, just 21 cities now account for half of all GDP. All but three of the 100 largest counties in America have gained population, while two-thirds of the counties with fewer than 25,000 residents have lost population.

“Incomes are diverging as the upper end pulls away, just as the fortunes of communities are diverging,” said Mark Muro, a senior fellow at the Brookings Institution’s Metropolitan Policy Program. “The income levels and vibrancy of big, often coastal cities are pulling away from those of everywhere else.”

That population shift represents an almost conscious self-segregation. More Americans now live in politically and demographically homogenous communities than ever before, and fewer of us say we regularly interact with people who do not share our political values. Urban areas are more diverse and better educated than at any point in the last century, while rural areas are becoming whiter, older and more conservative.

“The cultural generation gap between a diverse youth and older white population has brought to the fore divisions on political ideology and issues like immigration, education, environment, national health insurance, gun control and the role of government itself,” said William Frey, a demographer at the Brookings Institution. “The nation confronted different views of its politics and identity, representing a war between its demographic future and demographic past.”

The country’s two largest political parties have almost completely realigned along with the rest of society. Where conservative Southern Democrats once cut deals with liberal Northeastern Republicans, successive wave elections have created an almost uniformly liberal Democratic Party and an almost uniformly conservative Republican Party.

The Teens were “the decade when America became a genuine two-party democracy, with two truly distinct, nationalized parties having no overlap — for the first time in American political history,” said Lee Drutman, a senior fellow at New America, a center-left think tank.

That shift solidified itself across the decade. At the beginning of 2010, eight states had divided legislatures, in which Republicans controlled one chamber and Democrats the other. Today, only Minnesota is divided. Democrats controlled legislatures in Arkansas, Louisiana, Mississippi, Alabama, North Carolina, West Virginia and Iowa — all states controlled by the GOP today.

White Democrats held 37 congressional seats in states that were a part of the Confederacy; today, they hold only 19. The two states that still have equal or greater numbers of white Democrats in the House, Virginia and Florida, are the lone Southern states that voted twice for Obama.

The homogenization and polarization of our politics “threatened America’s governing institutions that were designed to require broad compromise, not narrow and constant partisan electioneering,” Drutman said.

The factors shaping America’s decade of decoupling do not end at our shores. Many of the same consequences of an uneven economic recovery and the growing urban-rural divide are evident in the United Kingdom’s vote to leave the European Union and elections last week that handed Prime Minister Boris Johnson a working majority in Parliament, a majority that runs through former Labour Party strongholds in rural regions.

Populist strongmen have risen to power in Turkey, Hungary and Brazil. The Arab Spring toppled governments in Tunisia, Egypt and Libya and spawned bloody civil wars in Syria and Yemen, and an emerging Latin Spring has destabilized Bolivia, Venezuela, Haiti and Chile.

As the Soviet Union pulled back from its satellite states in the late 1980s, a young political scientist named Francis Fukuyama penned an essay speculating about the dawn of a worldwide liberal order, what he called the End of History. The decade of decoupling, both in the United States and abroad, represented history roaring back.