An unfortunate truth about health care reform is that any universal insurance proposal is probably going to upset some number of middle-class Americans. Somebody is going to be asked to pay more for their coverage, be forced to give up the private policy they’re comfortable with, or buy insurance they don’t want. The question is how many voters you tick off, and how severely, en route to getting everybody insured.

These issues have been talked about to death during Democratic debates when it comes to Bernie Sanders–style single payer—which would move everybody onto one government plan (even if they’re happy with their current insurance), ban private coverage, and could leave some people paying more for health care than they do today, depending on how exactly it is financed. But lately, pundits have begun to point out that plans based on a public option involve some trade-offs too.

Consider the recent controversy over Pete Buttigieg’s health care platform. Like other moderates in the Democratic presidential race, the former South Bend, Indiana, mayor would create a new, government-run insurance plan and let Americans choose whether to buy it or stick with private coverage. Buttigieg has done a particularly good job marketing his version of the proposal, calling it “Medicare for all who want it,” a smart bit of branding so ringing with common sense that Joe Biden has recently co-opted it to describe his own, slightly different plan. When he’s talking to voters from the debate stage, Buttigieg’s core pitch is that, if you don’t like the public option, you won’t be forced onto it.

Except, as the Washington Post recently pointed out, you might be. In order to achieve universal coverage, Buttigieg’s proposal relies on a slightly roundabout mechanism called “retroactive enrollment,” which would essentially require Americans to buy into the public option if they fail to purchase any other health plan. It would work in two steps. First, the government would set up a so-called backstop fund to cover the uninsured by paying doctors, hospitals, and other providers for their care. Then, at tax time, people who never got around to obtaining their own coverage would be required to “retroactively” sign up for the public option—meaning that they would have to pay all of the back premiums they would have owed over the previous year, even if they didn’t seek any medical treatment during that time. Going uninsured to save money would no longer be a choice.

Buttigieg’s critics have suggested that retroactive enrollment will prove poisonous with voters, comparing it to a “supercharged” version of Obamacare’s individual mandate, the perennially unpopular and much litigated requirement that Americans buy health insurance or pay a penalty. “Instead of paying a $695 fine at the end of the year for being uninsured, you are hit with a bill to pay an entire year of premiums that could be ten times that amount,” People’s Policy Project founder Matt Bruenig, a vocal single-payer advocate, told the Post. “This will be a political nightmare.”

Nightmare may be a slightly strong word. One of the chief complaints about Obamacare has always been that the coverage available through its exchanges is expensive for families that don’t receive subsidies, and the high deductibles can feel like a ripoff. If Buttigieg’s reforms make care more affordable—and the ideas he’s put on paper, such as capping premiums at 8.5 percent of income for everyone, would indeed save a lot of families money—people might not mind being forced to buy it as much. That said, someone, somewhere is bound to get angry at being required to pay for health insurance, and will surely do a cable news hit or two to vent—especially if the government does a poor job explaining and publicizing retroactive enrollment and people end up with surprise bills for thousands of dollars in back premiums. Should Buttigieg really try to pass a plan like this, he will need to think very carefully about how to implement it in order to minimize the blowback.

So why is Buttigieg going down this road? After all, a public option can work just fine without forcibly enrolling the uninsured. If the government uses its negotiating power to reduce provider payments, it can offer a reasonably affordable health care plan that plenty of people will sign up for, and put downward pressure on the entire insurance market, without requiring people to buy coverage when they’d prefer not to. Some politicians seem to have realized that this would be the politically easier route. While Biden has cribbed Buttigieg’s language on the stump, his own health plan would only automatically enroll people eligible for free coverage, not those who’d have to pay for it. (He’s talked publicly about bringing back the individual mandate, but his official platform doesn’t mention it.)

But while a public option without forced enrollment might be an easier political sell, it won’t guarantee that every American has health insurance. That seems to be the conclusion among most of the think-tankers who study this issue. The Urban Institute has estimated that a public option plan without any kind of automatic enrollment would leave about 14.7 million Americans without any coverage, not counting the undocumented. You could probably lower that number by providing more generous subsidies. But you won’t zero it out. And leaving millions uninsured will result in real, continued hardships—unpayable medical bills, untreated sickness, and yes, death.

Banishing those sorts of hardships into the past is going to require ticking off at least a few people who don’t want to pay for health insurance. That’s true whether you favor single payer, which raises taxes, or a plan like Buttigieg’s that hinges on a public option. The question, again, is whether your proposal is bound to anger so many people that it’s politically unpassable, or is bound to be wildly unpopular once it passes. For now, the public option seems like a somewhat lighter political lift than full-bore “Medicare for All,” because it would probably be less disruptive to people who get insurance through their employer and are skeptical about being forced to switch onto an untested government plan. But no path to universal health care is going to make absolutely everybody happy.