When the American Medical Association — one of the nation’s most powerful health care groups — met in Chicago this June, its medical student caucus seized an opportunity for change.Though they had tried for years to advance a resolution calling on the organization to drop its decades-long opposition to single-payer health care, this was the first time it got a full hearing. The debate grew heated — older physicians warned their pay would decrease, calling younger advocates naïve to single-payer’s consequences. But this time, by the meeting’s end, the AMA’s older members had agreed to at least study the possibility of changing its stance."We believe health care is a human right, maybe more so than past generations," said Dr. Brad Zehr, a 29-year-old pathology resident at Ohio State University, who was part of the debate. "There’s a generational shift happening, where we see universal health care as a requirement."The ins and outs of the AMA’s policymaking may sound like inside baseball. But this year’s youth uprising at the nexus of the medical establishment speaks to a cultural shift in the medical profession, and one with big political implications.Amid Republican attacks on the Affordable Care Act, an increasing number of Democrats — ranging from candidates to established Congress members — are putting forth proposals that would vastly increase the government’s role in running the health system. These include single-payer, Medicare-for-all or an option for anyone to buy in to the Medicare program. At least 70 House Democrats have signed on to the new "Medicare-for-all" caucus.Organized medicine, and previous generations of doctors, had for the most part staunchly opposed any such plan. The AMA has thwarted public health insurance proposals since the 1930s and long been considered one of the policy’s most powerful opponents.But the battle lines are shifting as younger doctors flip their views, a change that will likely assume greater significance as the next generation of physicians takes on leadership roles. The AMA did not make anyone available for comment.Many younger physicians are "accepting of single-payer," said Dr. Christian Pean, 30, a third-year orthopedic surgery resident at New York University.In prior generations, "intelligent, motivated, quantitative" students pursued medicine, both for the income and because of the workplace independence — running practices with minimal government interference, said Dr. Steven Schroeder, 79, a longtime medical professor at the University of California-San Francisco.In his 50 years of teaching, students’ attitudes have changed: "The ‘Oh, keep government out of my work’ feeling is not as strong as it was with maybe older cohorts," said Schroeder. "Students come in saying, ‘We want to make a difference through social justice. That’s why we’re here.’"Though "single-payer" health care was long dismissed as a left-wing pipe dream, polling suggests a slim majority of Americans now support the idea — though it is not clear people know what the term means.A full single-payer system means everyone gets coverage from the same insurance plan, usually sponsored by the government. Medicare-for-all, a phrase that gained currency with the presidential campaign of Sen. Bernie Sanders, I-Vt., means everyone gets Medicare, but, depending on the proposal, it may or may not allow private insurers to offer Medicare as well. (Sanders’ plan, which eliminates deductibles and expands benefits, would get rid of private insurers.)Meanwhile, lots of countries achieve universal health care — everyone is covered somehow — but the method can vary. For example, France requires all citizens purchase coverage, which is sold through nonprofits. In Germany, most people get insurance from a government-run "public option," while others purchase private plans. In England, health care is provided through the tax-funded National Health System.American skeptics often use the phrase "socialized medicine" pejoratively to describe all of these models."Few really understand what you mean when you say single-payer," said Dr. Frank Opelka, the medical director of quality and health policy for the American College of Surgeons, which opposes such a policy. "What they mean is, ‘I don’t think the current system is working.’"But the willingness to explore previously unthinkable ideas is evident in young doctors’ ranks.Recent surveys through LinkedIn, recruiting firm Merritt Hawkins and trade publication NEJM Catalyst indicate growing support. In the March NEJM survey, 61 percent of 607 respondents said single-payer would make it easier to deliver cost-effective, quality health care.Delving further, that survey data shows support is stronger among younger physicians, said Dr. Namita Mohta, a hospitalist at Brigham and Women’s Hospital and clinical editor at NEJM Catalyst.But it’s unclear whether these findings reflect young doctors’ feelings about the policy or whether they are tapping in to broader frustrations with the American health system.Much like the general public, doctors often use terms like single-payer, Medicare-for-all and universal health care interchangeably."Our younger generation is less afraid to come out and say we want universal health care," said Dr. Anna Yap, 26, an emergency medicine resident at UCLA, who served as a medical student delegate to the AMA until this past June. "But how? It’s different in what forms we see."Younger doctors also pointed to growing concern about how best to keep patients healthy. They cited research that broadly suggests having health insurance tracks with better health outcomes."Medical students, I would say, are very interested in public health and improving social determinants of health — one of them being access to health insurance," said Dr. Jerome Jeevarajan, 26, a neurology resident at the University of Texas-Houston, referring to non-medical factors that improve health, such as food or housing.Some of the shift in opinion has to do with the changing realities of medical practice. Doctors now are more likely to end up working for large health systems or hospitals, rather than starting individual practices. Combined with the increasing complexity of billing private insurance, many said, that means contracting with the government may feel like less of an intrusion.The debate is, at this point, still theoretical. Republicans — who control all branches of the federal government — sharply oppose single-payer. Meanwhile, single-state efforts in California, Colorado and New York have fallen flat.Also, doctors represent only one part of the sprawling health care industrial complex. Other health care interests — including private insurance, the drug industry and hospital trade groups — have been slower to warm to catchphrases like single-payer or universal health care, all of which would likely mean a drop in income.But increasingly physicians seem to be switching sides in the debate, and young physicians want to be part of the discussion."There’s tremendous potential … to be at the table if single-payer becomes a significant part of the political discourse, and create a system that is more equitable," Pean said.__________Kaiser Health News is a nonprofit news service covering health issues. It is an editorially independent program of the Kaiser Family Foundation, which is not affiliated with Kaiser Permanente.