The so-called moderate Republicans promised they would not slash Medicaid. Conservatives vowed not to explode the national debt. Party leaders insisted that they would not lump a jumble of unrelated policies into a single enormous piece of legislation and rush that bill through Congress before any reasonable person had time to read it.

But President Donald Trump wanted his “big, beautiful bill” enacted in time to sign it with a celebratory flourish on America’s birthday. And so nearly all GOP lawmakers in the House and Senate, setting aside these and many other pledges, principles, and policy demands, did what the president desired.

The legislation that cleared the Senate and House this week is many things, and it does fulfill some core promises that Trump made as a candidate: The measure makes permanent his first-term tax cuts (and reduces some taxes even further), injects billions in new spending for immigration enforcement and national defense, and rolls back some of the incentives for clean energy enacted by the predecessor whom Trump loathes, Joe Biden.

Ultimately, however, its passage through narrow Republican majorities is the most consequential demonstration yet of how tightly Trump controls his party. To fulfill the president’s wishes and meet his arbitrary deadline, some Republicans reneged on pledges to oppose deep social-safety-net cuts, while others abandoned efforts to preserve tax credits that benefited their states and districts. Spending hawks who vowed to uphold some semblance of fiscal responsibility caved rather than stand firm for deeper cuts.

Annie Lowrey: A big, bad, very ugly bill

Democrats made all of these arguments many times over, to little avail. But so did one surprising Republican, Senator Thom Tillis of North Carolina, who opposed the bill and then immediately announced his retirement rather than face the electoral ramifications of infuriating Trump. Tillis has developed a reputation as a bipartisan dealmaker during his decade in the Senate. But he is not usually a renegade. Senators Susan Collins of Maine and Lisa Murkowski of Alaska vote more frequently with Democrats than he does. Others in the party had drawn brighter red lines during the debate over Trump’s bill. Once Tillis abandoned his bid for a third term, however, he became the GOP’s truth-teller. “I think the people in the White House—the amateurs advising the president—are not telling him that the effect of this bill is to break a promise,” Tillis said on the Senate floor, referring to the legislation’s health-care cuts.

Two of his colleagues, Senators Josh Hawley of Missouri and Ron Johnson of Wisconsin, took a different path. For months, Hawley had waged a campaign against cutting Medicaid, arguing as recently as May that doing so would be “morally wrong and politically suicidal.” Bit by bit, he softened his stance. He first acquiesced to an initial version of the bill that instituted work requirements for Medicaid, and then he accepted even deeper cuts in the Senate’s version. By the time the bill came to the floor, Hawley had given up entirely. Rather than block the bill, he vowed to try to stop the changes he voted for from being implemented over the coming years.

Johnson railed against the bill from the opposite direction, criticizing the rush to pass it and insisting on far deeper spending cuts rather than adding trillions to the debt. He held out a little longer than Hawley. Johnson initially voted to block the bill, relenting on Saturday night only after he and a few other conservatives had secured the GOP leadership’s support for an amendment that could effectively end the expansion of Medicaid under Barack Obama’s Affordable Care Act. But the proposal encountered swift resistance, and by the time of the final Senate vote on the megabill Tuesday, the conservatives had withdrawn the amendment. Johnson, like Hawley, had fallen in line.

Polls show that the Trump bill is deeply unpopular, but for most in the GOP, the public’s view has not been an overriding concern. Over the past two decades, both parties have become accustomed to thin congressional majorities and fleeting windows of opportunity to enact their agendas. When I spoke with Representative Tom Cole of Oklahoma, the chair of the House Appropriations Committee, earlier this year, he summarized the party’s attitude: “We could get nothing done, in which case I guarantee you, we’ll be punished” by the voters, Cole told me. But with just a three-seat House majority, he noted, Republicans might be damned either way. “History would tell you we would normally lose the majority in the midterms anyway,” Cole said. “So when you got it, you ought to use it.”

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The collapse of GOP opposition to the Trump bill in the Senate repeated itself in the House. There, too, Republicans from both ends of the party mounted seemingly firm stands against the proposal—when the House first considered the bill in May and then again after the Senate passed its version this week—only to fold under pressure from the president and GOP leaders. In a series of votes throughout the night, dissenters turned to supporters without winning any changes to the bill. The trend was foreseeable, if not inevitable. Nearly universally, Republicans backed the underlying tenets of the bill—preventing an across-the-board tax hike while funding Trump’s immigration crackdown—and they agreed on the urgency of passing it this summer. Even the measure’s few consistent critics, such as Senator Rand Paul and Representative Thomas Massie, both of Kentucky, wanted to extend the tax cuts.

So did Murkowski, the Alaska moderate. In 2017, she joined Collins and a defiant Senator John McCain of Arizona to thwart Trump’s attempt to repeal the Affordable Care Act. Murkowski has continued to oppose Trump occasionally during the early months of his second term. But she has acknowledged that the threat of retaliation from the president weighs on her and her colleagues. “We are all afraid,” Murkowski said in April. This time around, she negotiated carve-outs for Alaska from some of the worst effects of the Trump bill, drawing unfavorable comparisons to the backroom deals Democrats struck to win votes for the ACA.

“Do I like this bill? No,” Murkowski told Ryan Nobles of NBC News. “I tried to take care of Alaska’s interests. But I know that in many parts of the country, there are Americans that are not going to be advantaged by this bill.” In a separate statement, Murkowski referred to the legislation as “a bad bill.” Yet when it came up for a vote Tuesday, she provided the vote that ensured its passage.