The U.S. Chamber of Commerce surprised politicos everywhere when the typically Republican-friendly organization endorsed 23 freshman Democrats during last year’s election cycle — including two moderates in Virginia, Reps. Elaine Luria and Abigail Spanberger.

This week, however, the Chamber appeared to issue an ultimatum to those lawmakers: Oppose Democrats’ proposed $3.5 trillion tax and spending package or risk losing the business community and the Chamber’s support.

The warning shot came in a six-figure ad campaign targeting Democratic lawmakers in five competitive districts across the country, including Luria’s in Hampton Roads. The ads, which began airing on television Wednesday, urge voters to contact their lawmakers and tell them to oppose the package, which proposes an ambitious expansion of the social safety net and major policy responses to climate change, among other things.

The Chamber had promised to include the vote on this package in its annual scorecard that it consults to make its endorsements. The Chamber’s president and chief executive, Suzanne Clark, decried the tax and spending proposal as an “existential threat to America’s fragile economic recovery and future prosperity,” arguing a $3.5 trillion bill would exacerbate inflation. Clark also strongly opposed the tax hikes on corporations that Democrats have proposed to pay for it, arguing they would lead companies to cut jobs.

Other Democrats it endorsed last year and targeted in its ad campaign this week included Reps. Cindy Axne (D-Iowa), Angie Craig (D-Minn.), Antonio Delgado (D-N.Y.) and Josh Harder (D-Calif.), although the Chamber said it may roll out the ad in “many more” districts.

“These tax hikes would be a body blow to our economy — endangering our recovery and taking more hard-earned money from small businesses and working families,” the ad says. “Tell Representative Luria: Don’t knock us out with these massive tax increases.”

The Chamber did not respond to questions about the scope of the campaign in Luria’s district.

A spokesman for Luria, Owen Kilmer, said she was not available for an interview but said in a statement: “Congresswoman Luria is closely following the ongoing negotiations. She wants to see a final package that creates jobs, protects the environment, cuts taxes for working families and is fully paid for.”

In two tight races last year, both Luria and Spanberger touted the Chamber’s endorsements while pledging to back legislation to help struggling small businesses during the pandemic and voting for trade policies the Chamber supported, such as the U.S.-Mexico-Canada Agreement.

Neither lawmaker, however, has pointedly endorsed or opposed the overall $3.5 trillion spending package proposal as it stands now. And each has avoided drawing lines in the sand or making the kind of policy demands that have turned Democratic negotiations over the spending package into a morass of dealbreakers, colliding with negotiations over the roughly $1 trillion infrastructure bill.

Democrats intend to pass the bill through reconciliation, meaning it can pass the Senate with a simple majority and does not need to withstand the filibuster — but Democrats can’t afford a single defection in the evenly divided chamber, unless Republicans improbably cross over. Centrists including Sens. Joe Manchin III (D-W.Va.) and Kyrsten Sinema (D-Ariz.) have said they would not vote for a package with a $3.5 trillion price tag, prompting a meeting this week with President Biden, who asked them to define what scope they would support.

When asked her position on the overall price tag of the proposal as it stands now, Spanberger said in an interview Thursday that the reconciliation package remains “a moving target” and that she would be withholding judgment until a finalized version is set out in legislation. If the Chamber wanted to come out against the unfinalized figure, Spanberger said, “that’s their prerogative to share that.”

“There’s frankly so much posturing that I think what we should be doing is focusing on the programs that are positive and the programs that are meaningful to people and the programs we’re advocating for,” she said.

Spanberger has been most outspoken in support of a proposal to give Medicare the power to negotiate prescription drug costs, a proposal whose fate in the reconciliation package is uncertain after some moderate Democrats voiced opposition.

Spanberger ran for reelection last year on a promise to fight to lower prescription drug prices, saying constituents in her central Virginia district commonly raised the issue with her. She and Luria — and plenty of other Democrats — featured the issue in campaign ads as a top priority.

The legislation — the Lower Drug Costs Now Act, which passed the House in 2019 but died in the Senate — is projected to save $456 billion in federal spending over a decade, according to the Congressional Budget Office. And Democrats hoped those projected savings could be used to pay for other major health-care provisions in the budget reconciliation package, including the expansion of Medicaid and dental, vision and hearing benefits for seniors.

But throwing yet another kink in Democrats’ ongoing negotiations, three moderates — Reps. Scott Peters (D-Calif.), Kathleen Rice (D-N.Y.) and Kurt Schrader (D-Ore.) — said they would oppose the drug-pricing plan over concerns the existing proposal would hurt the pharmaceutical industry’s ability to develop drugs. That position echoes the opposition voiced by Republicans, the pharmaceutical industry and the Chamber. Schrader introduced a rival proposal that would much more narrowly limit the circumstances in which Medicare could negotiate with the pharmaceutical industry.

On Thursday, Spanberger joined four other Democrats from competitive districts in penning an op-ed in The Washington Post urging Congress to keep the provision that gives Medicare the power to negotiate drug prices in the reconciliation package.

Still, in an interview that afternoon, Spanberger stopped short of describing it as a dealbreaker for whether she would support the ultimate package.

“While people are posturing over dollar amounts, I’m focused on the fact that this particular piece of legislation would dramatically change people’s lives,” she said.