Demonstrators rally outside the Capitol in May. (Yuri Gripas/Reuters)

An organization that opposes the Republican effort to repeal and replace key parts of the Affordable Care Act is pressuring five GOP senators not to vote for the emerging legislation in a new $1.5 million ad campaign that begins Monday, officials with the group told The Washington Post.

Community Catalyst Action Fund, which bills itself as a consumer health organization, is targeting Sens. Lisa Murkowski (Alaska), Jeff Flake (Ariz.), Susan Collins (Maine), Dean Heller (Nev.) and Shelley Moore Capito (W.Va.) with television and radio ads urging them to vote no.

The ad campaign comes as other organizations are ramping up opposition to the Senate GOP effort. Last week, a coalition of medical and consumer groups held an event in Cleveland that was billed as the first of a series of gatherings to speak out against a bill that passed the GOP-controlled House and the direction that Republican senators appear to be heading. The coalition — which includes AARP, two hospital associations and four disease-fighting organizations — has said it will convene events in at least three other states in coming weeks, with the next one Wednesday in Reno, Nev.

The Community Catalyst TV ad, which targets four of the five senators (not Flake), begins with a scene of a young boy wheezing in his bedroom and his mother rushing to get his asthma medication from a bathroom drawer.

“When this happens, she isn’t thinking about the health-care bill in Congress,” the narrator says. “She isn’t thinking that it’ll force her to choose between filling his prescriptions or paying their mortgage.”

A television ad sponsored by the Community Catalyst Action Fund encourages viewers to call their senators to vote no on the Republican health-care bill. (The Community Catalyst Action Fund)

“But our senators should,” the narrator later concludes. “So when they vote on the new health-care bill, tell them to think about what’s right for our families and vote no.”

The ad campaign also includes radio commercials running in Alaska, Arizona, Nevada and West Virginia that argue the GOP effort will negatively affect seniors.

The senators targeted in the ads have expressed some reservations about the emerging Senate legislation or the process and timeline with which GOP leaders are crafting it. Majority Leader Mitch McConnell (R-Ky.) and a small clutch of aides are writing the bill behind closed doors as McConnell consults GOP senators.

He hopes to bring it to the Senate floor by the end of June. But it is not yet clear how or whether he can get the 50 votes he will need to pass the bill. Not a single Democrat supports the effort, meaning McConnell can afford only two GOP defections.

All of the lawmakers singled out by the group except Collins come from states that expanded Medicaid under the Affordable Care Act, known as Obamacare. That was a significant part of the decision to spend $1.5 million, Community Catalyst Executive Director Robert Restuccia said.

The House GOP bill would phase out Medicaid expansion in 2020. Many Republican senators have pushed for a more gradual phaseout in their bill, as well as preserving certain protections for preexisting conditions under the ACA not maintained in the House bill.

Republicans argue that their legislation will result in lower premiums. Democrats have warned of coverage losses that would occur under a bill to repeal and replace Obamacare.

The nonpartisan Congressional Budget Office estimated that the House bill would leave 23 million more Americans uninsured by 2026 than under current law. CBO projected that overall premiums would fall under the bill, though people with preexisting conditions would face higher premiums.

The ads were produced by the firm GMMB, which worked for the presidential campaigns of Barack Obama and Hillary Clinton.

Amy Goldstein contributed to this report.