That question routinely vexes most Democratic single-payer supporters, which is why her staff quickly softened her statement to note that she and other Democrats who support Medicare for all also support back-up plans, like a Medicare buy-in or a public option. People don’t like to be told that their health plans will go away. The basic unpopularity of that proposition—people don’t get to keep what they have—is perhaps the biggest political hurdle Medicare for all supporters face, and should their objectives prove untenable it makes sense for them to have contingency plans.
But it also makes sense for Democrats to fight for their ideals in the most compelling possible way, and as close as Harris came, I think she could have gone further. Before falling back to second-best options, single-payer supporters should try to persuade people who worry about losing their current health plans that they’ll be immediately and permanently better off if they make the jump—if we all do so, together, all at once, and then never again.
The wrong idea out there is that any transition to a new thing might be A) complicated and costly and therefore B) unpopular. A) is probably true. B) is only true because in our neoliberal world few can imagine that the complications and costs don't actually have to fall on individual voters who are already busy spending two hours on the phone with Comcast.
Why should voters bear the costs? The government can eat the costs and take care of the complexity and I can show up to the doctor with my medicare card and have it be paid for.
The "wonks" want every damn person in their country to play their Fantasy Health Care System video game because that's fun to them. The rest of us just want to go to the doctor without going bankrupt and then not even being able to discharge our medical debts in bankruptcy (thanks, Kindly Old Uncle Joe Biden and many of the rest of the Democrats). The way to avoid a costly unpopular transition is to not have it be costly and complicated... for us. It doesn't have to be. Why should it?
wonk voice: what people *really* want to do is shop for health insurance every year within a narrow time window on a nonfunctioning website powered by hamsters and Windows ME.