Democratic presidential candidate Sen. Elizabeth Warren, D-Mass., speaks during a town hall meeting at Grinnell College, Monday, Nov. 4, 2019, in Grinnell, Iowa. (AP Photo/Charlie Neibergall) (Marci Schmitt — Associated Press/The Minnesota Star Tribune)

The years since the 2010 Affordable Care Act's passage have driven home a clear message: Reforming health care is a monumental undertaking even when the policy prescriptions are relatively modest.

As the landmark law's 10th anniversary approaches, it's in legal peril a third time as another battle over its constitutionality likely heads toward the U.S. Supreme Court. Today consumers better understand the subsidies the law provides for insurance coverage, but the learning curve has been steep. Rolling out the technology required to implement the law, such as for online marketplaces like MNsure, has been rocky.

What's striking about these challenges is that they hobbled a law that built on the existing system of private health insurance and Medicaid, a popular public program in place since the mid-1960s. The ACA was not a radical change despite legions of critics saying otherwise. If it's been this hard to implement the law's modest reforms, imagine how daunting it would be to put a plan in place that would blow up the current health care system — the single-payer or Medicare for All proposals pushed most prominently by Democratic presidential contenders Sens. Elizabeth Warren and Bernie Sanders.

Warren and Sanders would make the federal government the nation's health insurer, which it already is for Americans 65 and older who depend on Medicare. Those who are not senior citizens would enroll in the program, or something like it, instead of buying private health insurance on their own or getting it through an employer. Proponents argue the approach would better control health care costs through administrative efficiencies and that it could eliminate out-of-pocket consumer costs, such as deductibles or coinsurance. Opponents, among other objections, are understandably alarmed about the still-uncertain costs of such a program and an already-in-debt federal government's capacity to take on a massive new responsibility.

The debate intensified in the past week when Warren released an outline of her plan's estimated costs, how it would work and how it could be paid for. The plan, written by two health care heavyweights, is a serious effort but an alarming read. Such a shift could reduce the nation's overall health expenditures but require $20.5 trillion in new federal spending over 10 years. That figure is far lower than other experts, even those from a progressive-leaning think tank, have calculated.

Then there are the political hurdles, even if Democrats controlled Congress. Close to half of Americans get their health insurance through employers. Even if their coverage might improve, millions would feel like they'd be losing their health plan. Fear of this change, and the backlash from it, may be enough on its own to endanger such a plan's passage.

But the Warren plan would pick political battles on multiple fronts. Those savings she intends to wring out of the system? The health care industry considers those savings to be "revenue." These special interests are among the nation's most powerful lobbies — especially insurers, who face an existential threat. Streamlining administrative costs or finding efficiencies elsewhere could also lead to layoffs or pay cuts within these industries. That could have an outsized impact on Minnesota where four of the 10 largest employers in the state are in health care delivery, according to the state Department of Employment and Economic Development.

The defense industry would be another hurdle, since Warren's plan calls to an $800 billion budget cut over 10 years to help pay for care. And she proposes raising corporate taxes and targeting wealth in a variety of ways — increases that many economists warn would hurt the U.S. economy.

No political or economic arguments are likely to deter Medicare for All advocates, however. They are a passionate group and their goal — health care for all — is just. But this not the only way forward, nor should it be. Less disruptive steps that build on the ACA, such as policies that would make prescription drugs more affordable or allowing consumers to voluntarily buy into Medicare, are better options that can garner broad support.

Steady progress isn't a revolution, but it can add up to revolutionary improvement. The presidential debate will be well-served if Warren's competitors counter this fantasy plan with a dose of reality.