Liz Truss’s rapid political demise came to an end on Thursday, when she announced her resignation just over six weeks after becoming Britain’s leader. Her agenda had stalled, her own party had turned against her, and commentators were debating whether she could outlast a head of lettuce. She couldn’t do it.

Despite widespread calls for her resignation, she had promised to carry on. But the heat on her grew minute by minute until there was no way out.

If you need to catch up, here is a primer on the fundamentals.

Ms. Truss was appointed to replace Boris Johnson, who was elected in 2019 but flamed out spectacularly after a series of scandals, forcing him to resign in July.

Ms. Truss was not elected by the general public; rather, she won a leadership election among Conservative Party members. To replace Mr. Johnson, the party’s MPs narrowed a field of candidates to two, who were then put to a vote by the party’s 160,000 dues-paying members.

Ms. Truss, 47, had been Mr. Johnson’s hawkish foreign secretary, a free-market advocate, and eventual Brexit supporter (after she changed her mind), winning over the party’s right flank despite her more moderate past.

It was never going to be easy for her. As Ms. Truss took office, the country was facing a disastrous economic picture, highlighted by energy bills that were expected to rise by 80 percent in October and again in January. It threatened to send millions of Britons, who were already struggling with inflation and other issues, into destitution, unable to heat or power their homes.

So, it was unwelcome news when her signature economic plans exacerbated the situation.

Her announced tax cuts, deregulation, and borrowing plans alarmed global investors, causing the British pound to fall to a record low against the US dollar. The Bank of England intervened to support government bonds in an unprecedented move to calm markets.

Her free-market ambitions were clearly undermined by the response. She was forced to reverse nearly all of the tax cuts this week, including a heavily criticized one on high earners, in a humiliating U-turn. She fired Kwasi Kwarteng, the chancellor of the Exchequer and a close ally of the plan, and implemented economic policies favored by the opposition Labour Party.

Her concessions did little to appease a growing rebellion within her own party, which had the potential to destabilize her in the same way that it destabilized Mr. Johnson.

The Conservatives, also known as Tories, had seen their popularity decline in public opinion polls following Mr. Johnson’s scandals, and their numbers plummeted to new lows as Ms. Truss took over. A Redfield & Wilton Strategies poll released this week revealed the lowest approval rating for a prime minister in its history, with 70% disapproving of Ms. Truss, including 67 percent of Conservatives.

According to the poll, if a general election were held today, 56 percent would vote Labour, while 20 percent would vote Conservative.

The Conservative Party’s dissatisfaction with Ms. Truss grew, and she was enveloped in a palpable sense of crisis. It boiled down to a frantic fight for her survival on Wednesday — “I’m a fighter, not a quitter,” she said while being grilled by members of Parliament.

Then there was even more chaos. Suella Braverman, Britain’s interior minister, resigned following an email breach, but in her resignation letter, she took aim at Ms. Truss, saying she had “concerns about the direction of this government.” A vote in Parliament was reported to have resulted in bullying, shouting, physical abuse, and tears. More Conservative members of Parliament openly demanded that Ms. Truss resign. Rumors of high-profile resignations circulated. It was challenging to keep up.

“In a nutshell, it’s total, absolute, abject chaos,” an iTV newscaster said. In an interview with the BBC, Conservative lawmaker Charles Walker did not hold back.

She announced her resignation to the king on Thursday, with a new leadership election scheduled for the following week.