House Speaker Paul Ryan (R-Wis.) speaks in the Rose Garden on Thursday after the House approved its health-care bill. (Jabin Botsford/The Washington Post)

It took a monumental effort by Republicans to sell one another on the health-care bill that narrowly passed the House on Thursday. It could take an even bigger effort to sell it to the public.

When the bill finally got through the House, President Trump and House Republicans staged a victory party in the Rose Garden at the White House. Everyone knew it was premature, but House leaders and a president who lacked a singular legislative victory were looking for any excuse to celebrate.

The victory party was a giant sigh of relief rather than an expression of confidence in the substance of the bill. What Republicans were celebrating was the simple fact that after one spectacular failure — having to pull the bill to avoid a loss on the House floor — and then weeks of tortuous intraparty negotiations, the votes finally came together to send the measure to the Senate. House Republicans got the monkey off their backs.

Many Republicans believed that another failure in the House would have been more damaging to their cause than plunging ahead into the unknown. Perhaps. The reaction from Republicans in the Senate spoke to the lack of confidence in the substance of the American Health Care Act as it emerged from the House — and likely to the feared political fallout if it was left untouched.

The bill will undergo surgery when senators start to work on it, and therefore the future of the legislation remains uncertain. Should the Senate produce something significantly different, the president and congressional leaders will face the choice of trying to reconcile the House and Senate versions or trying to jam the Senate bill through the House. The political calculus could argue for brute force. There’s still no guarantee of final passage of a health-care bill to revise the Affordable Care Act.

President Donald Trump looks to House Speaker Paul Ryan and other House lawmakers after Thursday’s health-care vote. (Jabin Botsford/The Washington Post)

All that is left to play out. No matter the ultimate outcome, however, House members have taken a fateful vote. There’s no current public polling about the bill that was approved Thursday. What was known about the first version of the bill, the one that couldn’t muster the votes to pass, was not encouraging for any Republican looking at a reelection campaign. Fewer than 1 in 5 Americans said they liked the earlier version. The more people knew, they more intensely they disliked it.

Few people outside the House fully understand the fine print of the new bill, and it’s likely many in the House aren’t totally fluent on its contents either. The Congressional Budget Office analysis of the earlier version highlighted the fact that, a decade from now, it would result in 24 million fewer people with health-care coverage than under the current Affordable Care Act. The House voted before the CBO issued its analysis of the revised bill, but some House Republicans are already attempting to debunk those unknown findings, as they did with the earlier CBO analysis.

The president was an energetic cheerleader in the effort to round up House votes and promote the bill, but he was hardly attuned to the details. He made statements on Thursday that he might regret. He said Obamacare is now dead. He said the House bill would reduce the cost of premiums and lower deductibles. Some people would see their premiums reduced under the House bill, according to the CBO — mostly younger people. Older Americans face higher premiums. They are part of the president’s constituency. That’s the impact a decade from now. Over the shorter term, the CBO has said the changes envisioned in the House bill would increase premiums more than under Obamacare.

Long before the final act plays out in Congress, the political fight over health care is in full force. The 2018 midterms will mark one more election in which health care plays a central role, as it did in 2010, 2014 and 2016. Those elections proved successful for Republicans, who made attacks on the Affordable Care Act a centerpiece of their campaigns. (President Obama always argued that the loss of the House in 2010 had more to do with high unemployment than with the health-care bill.)

The House vote had an instant impact on political forecasts. On Friday morning, the Cook Political Report shifted ratings on 20 House races — all to the detriment of the Republicans. The changes now put two dozen Republican seats in the competitive category, including one marked as leaning to the Democrats.

The ratings shifts should be read with several caveats:

(Jenny Starrs/The Washington Post)

● First, these elections are 18 months away, so predicting the future is risky.

● Second, Democrats haven’t exactly gotten their own house in order: The antics of House Democrats mocking their Republican counterparts during Thursday’s vote was as premature a declaration of victory as what took place in the Rose Garden later that day.

● Third, the state of the economy will influence voters’ decisions.

Still, take the changing forecasts as an early warning signal for the Republicans. They are an immediate indicator that what House Republicans did Thursday adds to the burdens of being the party that holds the White House during a midterm election. It is also a view of the politics of the House vote that is shared by any number of Republicans.

The House vote probably will contribute to an already-existing enthusiasm gap between Democrats and Republicans, one that’s been on display since Inauguration Day. Trump’s base remains supportive of the president, but there’s little dispute that the Democratic base is more energized than the Republican base.

Passage of Obamacare in 2010 energized Republican opponents far more than it energized Democratic supporters, but Democrats believe Republicans will carry an added disadvantage this time. Though Obamacare sharply divided the public, specific provisions, such as allowing children to stay on their parents’ plan until age 26 and the prohibition on denying coverage for people with preexisting conditions, were relatively popular. Key provisions of the Republican bill have been judged negatively, including the new change that would let states apply for waivers to loosen the requirements for covering people with preexisting conditions.

For Republicans in swing districts, the House vote represents a potentially big problem if energy is on the side of the Democrats. Of the 23 Republicans who sit in districts won by Hillary Clinton last November, nine voted against the House bill and 14 voted in favor of it. Of those nine, one Republican — Florida’s Ileana Ros-Lehtinen — already has announced her retirement, and Democrats see her seat as a prime pickup opportunity. Whether those negative votes will provide some protection for the remaining eight House members who run for reelection is another question.

That there are problems with Obamacare is no longer is in dispute; the law needs fixing. Insurance companies continue to withdraw from the exchanges or are threatening to do so in counties and in some states, in part because of financial losses and in part because of growing uncertainty about future rules and regulations.

The House has now spoken, controversially, putting members at risk. It will be up to the Senate to find a safer path.