After Donald Trump’s presidential inaugural address, the Republican delivered candid and rambling remarks to supporters in Emancipation Hall, alongside several House GOP leaders, including House Speaker Mike Johnson. Early on in his unscripted speech, the new president gently teased the Louisiana congressman about his tiny House majority — which Trump made worse.

“We gave [Johnson] a majority of almost nothing, and then I said — to make it tougher on him — let me take two or three of the people,” Trump said, referring to the fact that he chose some House Republicans to join his administration in a variety of posts. The president added that in the coming months, Johnson will be so frustrated, it’ll feel like “hitting your head on a wall.”

The House speaker chuckled politely, though this was one of few things Trump said on his first day that was true.

Indeed, shortly before the remarks, the House GOP conference did, in fact, shrink by one. The Hill reported:

Rep. Mike Waltz (R-Fla.) resigned from the House on Monday morning, as he prepares to join President-elect Trump’s Cabinet as national security adviser. Waltz’s resignation was read on the House floor just over an hour before Trump was scheduled to be sworn in, officially bringing the breakdown in the House to 218 Republicans and 215 Democrats.

The White House national security adviser does not require Senate confirmation. The former Florida congressman has already begun his new duties.

Complicating matters for GOP leaders on Capitol Hill, Waltz isn’t alone: Republican Rep. Elise Stefanik of New York, Trump’s choice to serve as the U.S. ambassador to the United Nations, will almost certainly be confirmed by the Senate in the coming days, which will create a 217-215 House.

Yes, there will be special elections to fill Waltz’s and Stefanik’s vacancies, as well as the vacancy left by former Republican Rep. Matt Gaetz of Florida, and GOP officials like their chances of keeping those seats. But as a practical matter, that doesn’t change the fact in the first few months of the new Congress, as Trump and his team look to Capitol Hill to advance controversial legislation, the balance of power will be 217-215.

As a matter of arithmetic, on key votes in which Democrats are united in opposition, that means the House GOP conference will have to be completely united to succeed. If even one Republican member balks, it will be enough to derail the party’s legislative endeavors. (A 216-216 vote constitutes failure. Bills need a majority to advance.)

Or as a recent NBC News report summarized, House Republicans will have “a zero-vote margin for defection” in the coming months. The report added, “Even when the party returns to full strength, the House majority could have trouble passing party-line legislation if a handful of members fall ill, have scheduling conflicts or experience weather delays preventing them from getting to Washington in time for key votes.”

Circling back to our earlier coverage, it’s worth emphasizing that the legislative math isn’t the only problem: House Republicans in recent years have become even more hostile toward compromise, more disdainful of bipartisan cooperation, more inviting of crises such as government shutdowns and debt ceiling showdowns, and more indifferent to the needs of GOP members from competitive, blue-leaning congressional districts.

Johnson struggled badly to lead his conference last year, routinely leaning on members of the House Democratic minority to conduct routine governance, and there’s no reason to believe his challenges will be any easier in 2025. On the contrary, with a smaller majority, his odds of legislative success are worse.

Since the 2024 elections, Johnson has repeatedly appeared on conservative media outlets and boasted about his party’s prospects in the near future. “Look, we’re excited about this,” the Louisiana Republican declared last month. “We’ve demonstrated already that we can govern with a small majority.”

The available evidence points in the opposite direction: The House Republican majority had effectively no accomplishments to speak of in the last Congress, and while the broader circumstances are clearly different — the GOP now controls the Senate and White House, which was not the case in 2024 — Johnson still hasn’t demonstrated that he and his team “can govern with a small majority.”

With Waltz out, that majority is now even smaller. Trump apparently thinks this is worth joking about, but I have a hunch the House speaker disagrees.

This post updates our related earlier coverage.