Sanders’s Medicare for All bill is built on the understanding that revolutions take time.

I’m a fervent supporter of Bernie Sanders’s Medicare for All bill, which he introduced Wednesday along with 16 Senate Democrat co-sponsors—and not only because I believe health care is a right and that a universal single-payer system is the best way to ensure that right.

I also support it because it diminishes the power of capital not just in our economy but in our politics as well.

I also support it because it’s aspirational—setting a long-term goal that will both motivate Democratic and progressive activists and clarify the Democrats’ purpose to an electorate that at times has been understandably unsure how or whether the Democrats champion their interests.

Most important, I also support it because it’s gradualist—expanding Medicare in its first tranche to cover just those Americans under 19 and over 49, then lowering the age for eligibility to 45, then 35, then making it universal, in subsequent years. The political implications of this gradualism may make it easier to assemble a congressional majority to enact this bill, and may also make it easier for progressive and centrist legislators in more conservative states or districts to support it in piecemeal fashion.

My first two supplemental reasons for backing the bill don’t require extensive explanation. Pharmaceutical companies, in which many private equity firms and hedge funds invest heavily, have long played an outsized role in our legislative process. The Affordable Care Act could not have passed if those companies had not secured a guarantee that the government would not compel them to subject their drug pricing to governmental negotiation or oversight, or if private insurers had felt their interests similarly threatened. The campaign contributions and independent expenditures that these companies make to members of Congress subvert disinterested legislating and the integrity of the democratic process. Single-payer takes these obstacles to democracy out of the game.

As to its aspirational aspects, Sanders’s bill does what political parties and movements need to do: set a clear goal that defines the party’s or movement’s purpose and can motivate adherents over the course of a long struggle. Sanders’s timing in introducing the bill also couldn’t be better: Coming on the heels of the victorious battle over the ACA’s would-be repealers (in which Sanders himself played a significant role), the bill’s unveiling comes at a time when the public’s belief that health care is a right, and the public’s support for government ensuring that right, are both higher than they’ve been in many years.

But by far the most strategically savvy aspect of the bill is its gradualism.

But by far the most strategically savvy aspect of the bill is its gradualism. Sanders, it’s important to recognize, has not made and does not make the perfect the enemy of the good. During the Republicans’ war on the ACA, he more actively defended that legislation—while at the same time making the case for going beyond it—than most of his peers, touring the country to rally the opposition to the GOP’s attacks. Likewise, the bill he just introduced, composed as it is of several time-specific steps, is designed to make it progressively easier for legislators to support and progressively more difficult for such entrenched interests as the insurance and pharmaceutical industries to defeat.

Suppose, as will likely be the case, that a legislative majority for the bill’s first tranche—expanding Medicare to Americans under 19 and over 49—emerges first, before there’s a majority willing to enact the entire package. Politically, it’s far less of a heavy lift to support a universal entitlement for children (who also incur low medical expenses) and for a slice of the population that’s worked for many years and is finding it more difficult to find remunerative employment in our brave new economy. That’s a debate that single-payer advocates should welcome, and that Big Pharma and the insurance companies should feel somewhat nervous about. I suspect the bill’s 17 sponsors would see it as a victory if that first tranche were enacted as a separated-out piece of legislation, with the understanding that they’d keep trying to secure majorities for the other tranches.

As the scope of Medicare’s clientele expands and as that of the private insurers contracts, the financial and political heft of the private insurers would contract with it. The fight to lower the age of eligibility to 45, then 35, then to make Medicare truly universal, would be one in which private insurers would have progressively fewer arrows in their quivers. An industry that provides insurance to 60 million Americans, and then 40 million Americans, has smaller profits and less clout in Congress than one that provides insurance to 150 million Americans.

It may not be Sanders’s intent to disassemble his bill into age-and-time-specific pieces of legislation. But the bill’s very design certainly makes that possible if it’s politically necessary, and Sanders’s own inclinations not to make the perfect the enemy of the good, and his understanding of the complexities of social change, suggest that he at least understands this may be the course that getting to single payer will take.

None of this is to suggest that enacting just the first tranche will be easy—it will, of course, require substantial Democratic majorities in both houses of Congress and a Democratic president. Compelling pharmaceutical companies to negotiate prices and simply expanding the populations covered by Medicare will provoke a massive opposition campaign from Big Pharma and insurance companies, and other forces that thrive under the health care status quo. But it’s easier to overcome those forces when the debate centers on the right to health care of children and longtime workers than it is to win an all-or-nothing battle that some on the left have advocated.

The gradualist approach in Sanders’s bill also permits Democrats and progressives to have a more flexible approach to their own elected officials and candidates. A liberal or center-left Democrat in a red state may face electoral extinction if she endorses single-payer. She may well be strengthened at the polls, however, if she backs Medicare for kids and the middle-aged. Rather than encouraging some on the left to create a single standard for candidate support—to wit, whether that candidate backs single-payer now—the Sanders bill creates a continuum that affords candidates the ability to position themselves on a sliding scale of support, depending on the politics of their state or district. Some on the left clearly want to cast elected officials who don’t or politically can’t support the entire package now into the eternal darkness; little Lenins at the Finland Station we certainly have with us. But Sanders himself has made no such argument, and his bill clearly invites the partial endorsement of Democrats who feel constrained from backing it in its entirety.

Besides, revolutions take time. They’re a process, not an overnight transformation. Bernie understands that; so should the left