When Senator Jerry Moran walked into a town hall meeting in Palco, Kan., last week, he knew he would get pointed questions about the Republican push to reshape American health care. But he probably wasn't expecting to hear from his own children's pediatrician.

Bob Cox, 73, rose and asked the Republican lawmaker why the United States invests heavily in the military to counter external threats but doesn't make the same commitment to caring for citizens who face internal threats, such as disease and injury.

What's more, Dr. Cox said afterward, the current Republican plan would only make things worse by pushing millions of people off health-care coverage and making it impossible for many rural hospitals to survive.

Story continues below advertisement

As Republicans push forward with their plan to undo the Obama-era reforms of the health-care system, they are running into formidable opposition from energized protesters, industry groups and even their own constituents.

Now Republicans are at a crucial juncture. This month is considered a critical and perhaps final window for the party's senators to reach an agreement on legislation that nearly all of them can support. If they cannot, it will be a humiliating admission that the party was more adept at critiquing the health-care system than fixing it – and possibly require them to negotiate with Democrats on future changes.

Once a rallying cry for Republicans, health care has turned into a painful dilemma. For seven years, following the 2010 passage of the Affordable Care Act – better known as Obamacare – Republicans have pledged to repeal what they described as a job-killing system that infringed on individual rights.

In the interim, however, many Americans have become accustomed to the Obamacare reforms, which expanded coverage for low-income Americans and guaranteed that insurers could not deny coverage to people based on their medical history. Meanwhile, the legislation that Republicans have proposed as a replacement is deeply unpopular: just 17 per cent of Americans approve of the bill under consideration by the Senate, according to a survey conducted late last month by Marist College.

The House of Representatives has already passed its own overhaul measure. Now the Senate is attempting to pass a bill using a process that would require only a simple majority in a chamber where Republicans hold 52 seats. But at least 10 Republican senators have expressed opposition to the measure, which would result in 22 million fewer people having health insurance over the next decade, according to an analysis by the non-partisan Congressional Budget Office.

The unpopularity of the Republican plan produced an unusual spectacle as lawmakers returned home last week for a short recess. Several Republican lawmakers got kudos from their constituents for defying their own party.

Susan Collins, a Republican Senator from Maine who has withheld her support for the measure, was congratulated by voters for her opposition as she walked in a parade on July 4. "Never before, in the 15 times that I've marched in this parade, have I had people so focused on a single issue," Ms. Collins told The New York Times. "I think it's because health care is so personal."

Story continues below advertisement

For moderate Republican senators like Ms. Collins, the current measure goes too far in reducing funding for Medicaid, the government program that provides health-care for low-income Americans and people with disabilities. For conservative Republican senators, their problem is the opposite: they believe the bill does not do enough to rescind the Obamacare reforms.

"There is not an overlap and there has never been an overlap" between the party's two camps, said Rodney Whitlock, vice-president of health-care policy at ML Strategies in Washington. Mitch McConnell, the Republican Senate majority leader, tried to guess at a possible compromise between the factions in proposing the current bill. "It's a hell of a difficult thing to do and it's pretty clear he was wrong," said Mr. Whitlock.

U.S. President Donald Trump promised voters during the campaign that he would end the unpopular aspects of Obamacare – including rising insurance premiums – while keeping all of the popular parts. "I cannot imagine that Congress would dare to leave Washington without a beautiful new HealthCare bill fully approved and ready to go!" the President wrote on Twitter Monday, referring to the imminent August recess.

Meanwhile, an unlikely coalition of activists and industry groups is keeping pressure on Republicans not to support the Senate bill. The largest national associations of doctors and hospitals have opposed it. So too has the powerful group representing the interests of Americans over 50.

The numerous groups protesting the measure include a network of disability activists that has held more than 30 actions since late June outside the offices of Republican senators. Some have ended in distressing images of people being hauled out of their wheelchairs as they are arrested by police.

"The disability community has never mobilized like this before," said Bruce Darling, a national organizer with ADAPT, a grassroots disability-rights organization. The proposed decrease in Medicaid spending will jeopardize state-level services that allow people with disabilities to live in their communities rather than in institutions. "What Americans do when their life and liberty is at risk is to fight for it," said Mr. Darling.

Story continues below advertisement

Back in the small town of Palco, Mr. Moran, the Kansas Senator, promised the room full of worried constituents that he would not support any bill detrimental to the health and well-being of Kansans. The Senator's apparent willingness to break with his party leadership was a welcome surprise for people like Dr. Cox, who has known Mr. Moran for years.

"We're very excited that he's saying that and appearing to take it seriously," said Dr. Cox.