Health Care, London, Mosul: Your Weekend Briefing

Here are the week’s top stories, and a look ahead.

1. Republican infighting has led to the biggest defeat yet for President Trump’s young administration.

The G.O.P. plan to repeal and replace the Affordable Care Act collapsed as the House leaders pulled the legislation in the face of a revolt among Republicans. The decision exposed the civil war within the party and raised questions about the consequences for the Trump administration’s aggressive agenda and next year’s midterm elections.

The president, in a telephone interview, argued that the situation would turn out in his favor. “The best thing that could happen is exactly what happened — watch,” he said.

His administration also granted a construction permit for the Keystone XL pipeline, reversing the Obama administration’s policy.

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2. London suffered its most serious terrorist attack in more than 10 years.

Investigators have been trying to learn how a 52-year-old former English teacher and Muslim convert was set on the path of extremism and whether others were involved in planning his attack.

He plowed a sport-utility vehicle into a group of pedestrians on a bridge outside Parliament on Wednesday, then got out wielding a knife. He killed four people and injured dozens before being fatally shot.

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3. The U.S.-led military coalition in Iraq confirmed that scores of civilians were killed at the site of recent airstrikes in Mosul, the Islamic State’s last stronghold in Iraq.

But the deaths occurred a few days after the strikes, they said, when a targeted building fell. They are trying to determine whether the collapse was caused by the strikes — or perhaps by an ISIS bomb.

U.S. officials said a surge of reported civilian deaths from strikes in Iraq and Syria reflect the intensified campaign against ISIS, not a change to strict rules of engagement.

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4. “Why are you doing this? What are you doing?”

Those were among the last words of Timothy Caughman, a 66-year-old New Yorker who lost his life in one of the week’s notably troubling episodes.

He was scavenging for cans when, the authorities say, he was killed by this sword-wielding 28-year-old white man who had come from Baltimore on a mission to kill black men in the most public way possible.

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5. Senate Democrats are vowing to filibuster the Supreme Court nomination of Judge Neil Gorsuch, whose confirmation hearings ended on Thursday.

Republican leaders have accused Democrats of using “obstructionist tactics” to thwart a vote.

Last year, the Republicans refused to consider President Barack Obama’s nominee to replace Antonin Scalia, Judge Merrick Garland.

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6. Landmark internet privacy protections are nearly certain to be dismantled.

Within days, the House is expected to pass a measure that the Senate approved last week. It would allow internet service providers to track and share customers’ browsing and app activity without obtaining their permission.

Republican supporters of the legislation said the regulations, created during the final days of the Obama administration, were onerous and stifled innovation.

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7. For a year, our reporters have been following Syrian refugee families and the Canadians who have helped them resettle in Toronto. Now, in Month 13, the sponsors are trying to let go.

The everyday Canadians who stepped up to help are stumbling, as are the Syrian families trying to go forward on their own. “The honeymoon is over,” said one sponsor, a retired teacher.

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8. Very good news for California: A wet winter has blanketed the ridges of the Sierra Nevada range with a remarkably thick snowpack, which is beyond welcome after years of drought.

The snowmelt will trickle down to irrigate crops, fill glasses and help sustain life in an arid state. Our collection of maps and photographs lets you share in the relief.

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9. Arkansas’ plans for the rapid-fire executions of eight inmates next month have hit an snag.

State law requires at least six witnesses to an execution, as a guarantee of proper procedures. Coming up with enough for all eight cases, scheduled over just 10 days, isn’t easy.

The state corrections director has had to begin personally seeking volunteers.

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10. “Money.”

That’s what the comedian Dave Chappelle said when Jimmy Kimmel asked why he decided to end a 13-year gap between standup specials with not one, but two last week. (Netflix reportedly paid him $60 million.)

Our critic said the specials showed that the long-absent Mr. Chappelle had changed: He “not only has a new kind of gravitas, but he has also embraced his status as an older comic with mature worries, like schools for his kids and growing old with his wife.”

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11. Odds are your bracket has bust or is on the brink of it at this point. Even so, N.C.A.A. basketball is rolling on toward the Final Four next weekend.

In the men’s tournament, Gonzaga will be there for the first time, and Oregon for the first time since 1939. The last two spots will be decided today: Florida takes on South Carolina (2:20 p.m. Eastern on CBS), and top-seeded North Carolina faces Kentucky (5:05 p.m. on CBS).

In the women’s tournament, it’ll be UConn against Oregon on Monday. For the other three spots, top-seeded Notre Dame faces No. 2 Stanford today (12 p.m. on ESPN) and No. 1 Baylor faces second-seeded Mississippi State (7:30 p.m. on ESPN). Florida State will play South Carolina on Monday.

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12. Think you’re having a rough morning? As hard as getting out of bed on a Sunday may seem, it’s nothing compared to what our science writer found about when animals rouse from the torpor of hibernation.

For instance, the black bear goes through weeks of feeling lethargic, eating bugs and plants before building up an appetite for salmon.

But perhaps there’s one thing to envy: The bears wake up having shed up to a third of their body weight.

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13. In other bear news, Bao Bao, the 3-year-old panda born at the National Zoo in Washington, stepped out on Friday for her first public appearance at her new home in China.

When it comes to cuteness, if there is anything than can rival a young panda playing and climbing, it might be the children who dressed as pandas to celebrate Bao Bao’s debut at the Dujiangyan base of the China Conservation and Research Center for the Giant Panda in Sichuan Province.

Have a great week.

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Photographs may appear out of order for some readers. Viewing this version of the briefing should help.

Your Weekend Briefing is published Sundays at 6 a.m. Eastern.

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