The real sign of how Bernie Sanders changed the Democratic Party can be seen not just in shifts in the Democratic Party platform, but in how the party’s current leader, Barack Obama, has altered his own posture. Last month he endorsed the expansion of Social Security, a huge victory for activists pushing the party to improve retirement benefits. And this week, in a special communication to the Journal of the American Medical Association, Obama endorsed a public health insurance option to enhance the Affordable Care Act, his signature legislative achievement.

This puts Obama in line with his preferred successor, Hillary Clinton, who recently reiterated her support for a public option and for allowing Americans between 55-65 to buy into Medicare. Both policies tilt toward Sanders’s vision of universal coverage.

Obama included the public option in his 2008 campaign platform, and maintains in JAMA that in the original debate over the ACA, “I supported including a Medicare-like public plan.” But he fails to mention that in the summer of 2009 he made a deal with the hospital industry to keep the public option out of the final bill, in exchange for the industry’s support and agreement to $155 billion in payment reductions.

We can’t know whether concessions to industry were critical to get the ACA passed, and whether the public option, which had the most grassroots support of any element of health reform, should have been salvaged. But the more important question is: What changed between 2009 and today for the president to view the public option as an essential component of the overall law?

The cynical will grumble that Obama is merely making a rhetorical shift for supporters in an election year, at a time when he knows he cannot pass anything resembling a public plan. But I think something is afflicting Obamacare that only a public plan can fix—and the hospital industry may even agree.