It’s been 24 days since Nancy Pelosi was sworn in as speaker of the House of Representatives. Some Democrats regard the California congresswoman as a “status quo” speaker—a less-than-inspiring figurehead for a remarkably diverse and progressive Democratic caucus.

But on Friday, Pelosi managed to pull off what some are calling the first undeniable legislative blow to the Trump presidency. She secured an end to the government shutdown without giving Trump the one thing he wanted in exchange—funding for the wall at the US-Mexico border—and did so just days after informing Trump that he would not be permitted to deliver the State of the Union address in the House chamber until the government was open again.

Whatever one’s politics, it’s hard to deny that Pelosi is on a roll. But what has her success at furthering her party’s objectives in the past month taught us about the president?

1. Trump is not ‘capable of sustaining an unsustainable position.’

At countless points during the last two years, the president has seemed to get away with things that no other politician could survive. But with a Democratic majority now in the House, that indestructible veneer has showed its first major crack. After owning the shutdown on camera—something Pelosi goaded him into doing—it became increasingly untenable for Trump to allow it to continue. As Ezra Klein wrote over at Vox:

Pelosi has proved what many didn’t believe about Trump: that he is subject to the normal laws of political gravity, and that for all his bluster, he is no more capable of sustaining an unsustainable position than any other politician.

2. Trump’s backers have a clear red line.

While this isn’t an entirely new insight, Pelosi’s coup of ending the shutdown has shown that the loyalty of Trump’s base has its limits. While pundits have hypothesized the president may hope to use the wall as a cudgel and rallying cry in the 2020 election, the president’s ardent supporters are signaling that they want a wall, and they want it this term.

#TrumpCaved was trending after the deal was reached, and high-profile supporter Ann Coulter withdrew her support for the president on Bill Maher’s show on Friday night.

3. It’s possible to “out-Trump” Trump.

Throughout the 35 day shutdown, Trump repeatedly said that he would not allow the government to reopen without funding for the wall. At times, he intimated that he would allow it to continue for months. But, as Chris Cillizza pointed out at CNN, Pelosi’s strategy worked because she essentially used the same tactic: Refusing to give any ground. She did it over and over, and got her party to do it with her.

What Pelosi seems to understand better than past Trump political opponents is that giving ANY ground is a mistake. You have to not only stand firm, but be willing to go beyond all political norms—like canceling the SOTU—to win. Which is what Pelosi did this week. Twice.

With the end of the shutdown secured, Pelosi is still demonstrating her willingness to play hardball. She told reporters that despite the deal, Trump still won’t be delivering the State of the Union on its original date of Jan. 29.

“What I said to the president is when the government is opened we will discuss a mutually agreeable date,” Pelosi said. “I’ll look forward to doing that.”

Correction: This article originally said that Pelosi became the first female speaker of the House this month. She earned that distinction during a previous appointment as House speaker in 2007.