Physicians for a National Health Program is a left-of-center advocacy group that supports a government-run single-payer healthcare system for the United States. The organization operates in two capacities: as a research group that publishes studies supporting government-run healthcare and as an activism arm for building support for such policies. 
Physicians for a National Health Program leadership advised left-wing U.S. Senator Bernie Sanders’ (I-VT) 2016 Presidential campaign. 
Physicians for a National Health Program was founded in 1987 by Steffie Woolhandler and David Himmelstein. According to a 2003 New York Times interview, they “became exasperated with what [Woolhandler] felt was the conservatism of many medical professionals” and sought to persuade policymakers and physicians to support government-run healthcare. 
Initially, Physicians for a National Health Program focused on publishing research in peer-reviewed journals, such as The New England Journal of Medicine  and JAMA.  A 2003 article published in the latter received the endorsement of 8,000 physicians, but the New York Times noted that at the time, there were 836,000 physicians in the country.  It later began branching out into activism work and to date, it currently has at least one chapter in 32 states. 
More recently, the organization has come out in support of the “Medicare for All” government-run healthcare bills proposed by U.S. Senator Bernie Sanders (I-VT) and Rep. Pramila Jayapal (D-WA).  The statement in support of Rep. Jayapal’s bill quoted Physicians for a National Health Program’s Adam Gaffney saying that “Congress shouldn’t be distracted with incremental plans like a Medicare buy-in or public option.”
Physicians for a National Health Program continues to regularly publish research supporting government-run single-payer healthcare. . They also occasionally update their “Physicians’ Proposal for Single-Payer Health Care Reform,” the most recent iteration of which was published in 2016 and entitled, “Beyond the Affordable Care Act.”  It is published by their “Working Group on Single-Payer Program Design,” made up of co-chairs Adam Gaffney, David Himmelstein, Steffie Woolhandler, and Marcia Angell.
The organization is presently looking to expand its chapters throughout the country and provides existing groups with stipends and training opportunities.  It also has a student activism arm, Students for a National Health Program, which has held annual summits since 2015. 
Outside of its chapters, it maintains a bureau of speakers who can be contacted to speak at public events. 
The organization has two levels of leadership: its Officers and a National Office Staff . Its current President, Dr. Adam Gaffney, regularly publishes on his blog The Progressive Physician and has advocated for government-run healthcare on media outlets like Fox Business and NBC. 
The only paid officer is executive director Matthew Petty, who makes $60,000 a year, as of 2017. 
Co-founders Steffie Woolhandler and David Himmelstein—who now work in the organization as Secretary/Board Member and Newsletter Editors, respectively—served as health policy advisors on Senator Bernie Sanders’ 2016 Presidential Campaign. 
Tax filings by Physicians for a National Health Program show total revenues of $943,602 and total expenses of $958,174.