Imagine if you were a foreign leader surveying the political chaos in the United States:

  • In the Senate, one of the two party leaders, who’s 81 years old, has twice recently frozen in public, unable to speak.

If you were an ally of the U.S., you’d have to be worried. If you were an enemy, you’d have to be pleased.

“To many watching at home and abroad, the American way no longer seems to offer a case study in effective representative democracy,” Peter Baker of The Times writes. “Instead, it has become an example of disarray and discord, one that rewards extremism, challenges norms and threatens to divide a polarized country even further.”

Many factors have contributed to this turmoil. Decades of stagnant living standards have caused voter frustration. Social media, along with the rise of a cable television network willing to promote falsehoods, has inflamed discourse. The decline of institutions — churches, labor unions, once-dominant local employers — has left Americans feeling unmoored. And aging political leaders have failed to groom strong successors.

But the single largest source of the chaos is the Republican Party.

I don’t say that lightly. Readers of this newsletter know that I think there is plenty of evidence that the Democratic Party also has problems. It has struggled in recent years to come up with effective policies on Covid school closures, illegal immigration and several other issues. Many working-class voters consider the party to be disdainful of them, which helps explain why its longtime troubles with white voters have recently spread to voters of color.

Still, every major political party has weaknesses. Despite theirs, the Democrats remain a functional party by almost any standard. Their moderate and progressive factions frequently work together. President Biden, like Barack Obama before him, has passed a long list of substantive legislation. Congressional Democrats have remained impressively united for two decades.

The Republican Party, by contrast, is both fractured and increasingly extreme. Tens of millions of Republican voters have embraced beliefs that are simply wrong: that Obama was born in Kenya, that Donald Trump was cheated out of re-election, that Covid vaccines don’t work, that human beings aren’t causing climate change. A crowd of Republican-aligned protesters violently attacked the Capitol in 2021, assaulting police officers and causing several deaths. Prominent Republican politicians, including Trump, have spoken positively about that attack and more generally about political violence.

Kevin McCarthy’s downfall as speaker is the latest sign of the party’s drift toward radicalism. He lost his job because a group of hard-right House members was furious with him for conducting policy negotiations that are inherent to democratic governance. “The ouster captures the degraded state of the Republican Party in this era of rage,” wrote The Wall Street Journal editorial board, a reliable voice of conservatism.

When my colleagues and I asked democracy experts this week how to make sense of the country’s political turmoil, they emphasized that the central explanation was the Republican Party:

  • “The democratic system needs two viable parties,” Sarah Binder, a political scientist at George Washington University, said. “You need a set of leaders on both sides that have the confidence of their followers and have some understanding of the rules of the road.”

  • “In my lifetime, this is the greatest challenge that I’ve seen coming at us,” said Joseph Ellis, a Pulitzer Prize-winning historian.

  • Daniel Ziblatt, a co-author of the recent book “Tyranny of the Minority,” told me that the structure of the American political system was partly to blame: The Electoral College, the Senate and gerrymandering have allowed Republicans to wield power without appealing to most Americans. “Our constitution in this way is one of several factors radicalizing the Republican Party, leading it to turn away from democracy itself,” Ziblatt said.

  • “I think the country’s political class is aging and underperforming in many ways — I’m a longtime critic of gerontocracy. But that’s a second-order problem,” Brendan Nyhan of Dartmouth College said. “The first-order problems by far are the state of the G.O.P. and the electoral rules and institutions that make the threat it poses so significant.”

Even with all these problems, there are reasons for optimism. The Republican caucus in the Senate is more functional than in the House. Federal judges and election officials, from both parties, blocked Trump’s efforts to overturn the 2020 election. Candidates who endorsed his lies fared poorly in the 2022 midterms. It’s possible that a more functional Republican Party, committed to both conservatism and American democracy, will emerge in coming years.

But it is not assured. “Events of recent weeks have reminded us that the authoritarian threat isn’t going away,” Nyhan said.

Detective work: A lucky break and old-fashioned police work led to the rescue of a missing 9-year-old in New York.

Travel 101: Make sure you don’t bring bedbugs home from vacation (especially if you go to Paris).

Kenergy sanctions: Warner Bros. no longer releases films in Russia. But theaters have found a way to screen “Barbie.”

Lives Lived: James Jorden was an influential writer and editor who fused high culture and punk aesthetics in his opera zine-turned-website Parterre Box. He died at 69.

M.L.B.: In a surprise result, the Texas Rangers swept the Tampa Bay Rays in the Wild Card Series, winning 7-1.

Bowling and batting: The Cricket World Cup starts today and will be played in 10 locations across India.

Soccer: The 2030 World Cup will take place across three continents, as part of the celebration of the tournament’s 100th anniversary.

Geniuses: Patrick Makuakane, a hula choreographer in San Francisco. María Magdalena Campos-Pons, a multimedia artist in Nashville. Courtney Bryan, a composer in New Orleans. They are among this year’s class of MacArthur Fellows — commonly known as the “genius” awards — which reward innovators in arts, science and more with an $800,000 grant.

See the full list of winners, which also includes a U.S. poet laureate, a hydroclimatologist and a democracy advocate.