As the American Health Care Act squeaked by in the House of Representatives on Thursday, some Democrats began singing “Na-na na-na, na-na na-na, hey, hey, hey, goodbye!” and waving at their Republican counterparts—not so subtly intimating that they would be voted out of office in 2018.

But for progressive groups and activists, it wasn’t a day for celebration or an opportunity for pre-emptive taunting. It was a day to prepare for all-out war.

“Every group working to unseat Republicans in 2018 is seeing an explosive growth in fundraising,” Ben Wikler, Washington director for MoveOn, said in a phone interview with The Daily Beast on Thursday. “The electoral blowback has already begun.”

The AHCA, whose passage in the House was heralded as a victory by President Donald Trump, essentially limped to the finish line after a failure to get to a vote in March.

Twenty Republicans voted against the bill, with many not knowing what exactly was in it or how much it would cost. The bill itself does not repeal Obamacare but rather gets rid of the mandate that requires people to carry insurance.

Instead a new amendment to the legislation, offered by Rep. Tom MacArthur, would allow some states to charge higher premiums for people with pre-existing conditions (including but not limited to diabetes, pregnancy, and cancer) and the option to opt out of essential health benefit requirements from the Affordable Care Act.

“We’re going to get this passed through the Senate, I feel so confident,” Trump said in the Rose Garden during his remarks after the vote. “[Obamacare’s] been a catastrophe. and this is a great plan. I actually think it will get even better.”

And that’s the concern for some liberal and leftist groups—that an iteration of this bill could actually make it through the Senate despite the fact that no one knows how much it would cost to implement or how many people would lose their insurance. (The Congressional Budget Office’s score on the bill in March estimated that 24 million people would lose their insurance by 2026.)

Hours before Trump was set to land in New York City on Thursday—for the first time since his inauguration—protesters had already gathered outside DeWitt Clinton Park in Hell’s Kitchen. The demonstration, one of at least three scheduled in the city, brought together the Working Families Party, Women’s March, Million Hoodies, and Iraq Veterans Against the War.

Joe Dinkin, national communications director for WFP, estimated that at least 2,500 people were in attendance for the protest, which proceeded down the West Side Highway toward the Intrepid Sea, Air & Space Museum, where Trump was set to meet with Australian Prime Minister Malcolm Turnbull. The protesters, carrying signs that read “Big Apple Hates This Rotten Orange” and “This Village Doesn’t Want Its Idiot Back,” inevitably beat the president to the site of the Intrepid because he delayed his arrival to the event to see how the vote shook out.

The protest, which drew a lot of honks of drivers and a couple of middle fingers, was initially intended to let the president know how unpopular he is in his hometown. But as the House finalized its votes moments before the procession began, health care was on everyone’s mind.

“I’d say they passed the health sickness bill,” 69-year-old Peter Kinoy told The Daily Beast over the clanging of pots and pans, intended to drown out Trump. “That it’s going to kill people, that’s the biggest concern. I mean that people are going to die because they can’t afford the jacked-up premiums. People are going to die because they’ve got pre-existing conditions that are not going to be covered. The problem is that people are going to die for consolidation of wealth. And that’s not right. Why should people die so a few people get richer?”

Of the 217 House members who did vote for the bill, a sizable share was made of up vulnerable members. Some 14 of the 23 House Republicans in districts that Hillary Clinton won in the 2016 presidential election supported the bill, including all seven in California. So the short-term payoff of a “win” may spell disaster in midterm elections.

For now, progressive groups smell blood in the water. Wikler told The Daily Beast that on Thursday alone, MoveOn held 29 protests in Republican House districts and four in House Speaker Paul Ryan’s district in Wisconsin. On top of that, some 10,000 calls were made to House Republicans who were considered swing voters on the bill.

“I think this version of Trumpcare is going to be dead as a rock as soon as the CBO score comes out,” Wikler told The Daily Beast.

Some Democrats on the Hill, as well as progressive groups, are not satisfied with just opposing Trumpcare as the ultimate goal but would rather craft a single-payer alternative.

Wikler said that “ultimately Democrats should push for Medicare for all” but that “in the immediate moment, the critical thing is to wage all-out war against Trumpcare.”

House Minority Leader Nancy Pelosi, who spoke forcefully against the AHCA on Thursday, expressed skepticism that American citizens could support a single-payer model. “No, I don’t,” Pelosi said when asked whether single payer should be part of the Democrats’ platform in 2018. She has said in the past that she is personally pro-single payer.

Sen. Bernie Sanders, who has introduced legislation pushing for single payer, similarly blasted the vote on AHCA, saying: “The bill that Republicans passed today is an absolute disaster. It really has nothing to do with health care. It has everything to do with an enormous shift of wealth from working people to the richest Americans. This bill would throw 24 million Americans off of health insurance—including thousands of Vermonters—cut Medicaid by $840 billion, defund Planned Parenthood, and substantially increase premiums on older Americans. Meanwhile, it would provide a $300 billion tax break to the top 2 percent and hundreds of billions more to the big drug and insurance companies that are ripping off the American people.”

Dinkin of WFP told The Daily Beast that his party supports single payer, and Matt Howard, co-director of Iraq Veterans Against the War, said it’s definitely something to consider.

“I personally think that Obamacare was a start but that in order to ensure that health care costs don’t continue to devastate families across the country, we have to push further,” Howard told The Daily Beast after Thursday’s Intrepid protest. “Single payer is definitely an option we have to consider soberly. What is 100 percent clear to me is that Trumpcare, if passed, will be a stark rollback of our rights and will land squarely on the backs of millions of working families.”

Our Revolution, a political action organization founded after Sanders’ presidential bid, is also pushing for single payer as the ultimate goal.

“Today, Republicans succeeded in passing a disastrous bill to strip health care from millions of people,” president Jeff Weaver, Sanders’ former campaign manager, said in a statement provided to The Daily Beast. “Donald Trump and Republicans in Congress are giving billions in tax breaks to the wealthy on the backs of working men and women who will face higher premiums and reduced access to the lifesaving medical care they need.”

“Our Revolution will continue to fight against Republican efforts to strip people of their health care and support efforts to build on the strength of the Medicare program and create a Medicare for All system,” he continued.

David Duhalde, deputy director of the Democratic Socialists of America, whose membership has ballooned since the presidential election, told The Daily Beast that DSA will “push back against the bill through grassroots activism.”

“Today, the DC DSA led a protest outside the Capitol,” Duhalde said. “More broadly, our locals will continue to push for Medicare-for-All type reforms at the state-level bills to provide a working alternative to both the ACA and ACHA.”

As the dust settled Thursday, the House headed to recess, having forced through the bill and shifted responsibility to the Senate. And progressive groups took special notice—hoping that the outcry from constituents when Republicans return home will provide necessary momentum for continued opposition.

“Our Revolution will be organizing a calling campaign to ensure this treacherous bill does not pass the Senate,” the group said in a statement provided to The Daily Beast. “An exact timeline and specifics are not in place yet, but we will be working with members of past coalitions to target key senators and make sure they know their constituents expect them to vote to protect their health care rights.”

Dinkin said WFP will be running a similarly active campaign.

The more people hear about the bill, the more they will come to hate it, said Wikler of MoveOn.

“This is both an unbelievably vicious bill and a politically toxic bill,” he told The Daily Beast. “The more the public learns about it, the more Republicans are going to discover their base disintegrating from beneath.”

Wikler added that above and beyond contentious town halls in their home districts, Republicans might be staring down constituents everywhere they look.

“The bigger challenge for Republicans will be the booing and the hostile encounters they get at the grocery store and church.”