Molly Ball writes for the Wall Street Journal about challenges facing the new conservative governing majority in the nation’s capital.

The speaker vote was a crucial early test for Trump’s incoming administration and his Republican Congress. While his transition effort has been focused and purposeful, his policy priorities and ability to execute on them remain open questions as he returns to Washington.

The central irony of the Republicans’ situation is that while the party is as unified and optimistic as it has been in decades, the arithmetic now is unforgiving. With just 219 votes in the 435-seat chamber, Johnson has just one vote to spare on party-line votes like Friday’s. Even if 99% of Republicans agree, it will not be enough to pass legislation; they will need not just unity, but virtual unanimity.

So while the vibes are far better than the last time the GOP assumed the majority, when Kevin McCarthy only won the speakership after a dayslong multiple-ballot ordeal, the math for Johnson is worse.

Johnson’s principal strategy has been to stick as close to Trump as possible—he spent New Year’s at Mar-a-Lago—banking on the president-elect’s sway with the GOP base to put pressure on the speaker’s Republican detractors.

The gambit appeared to pay off, despite doubts in the capital that he could win the speakership after one vote. In the final days leading up to Friday’s vote, Trump made calls and posted on social media in support of Johnson, an effort that appeared to persuade many Johnson skeptics. People close to Trump say he is lukewarm on the speaker, viewing him as likable but of questionable toughness. But the men’s relationship will be crucial to their party’s prospects in the coming months.

The question going forward will be whether Trump and Johnson can keep everyone in the tent as they embark on what they have touted as an ambitious policymaking spree.