Editor's Note: Julian Zelizer is a history and public affairs professor at Princeton University and the author of "The Fierce Urgency of Now: Lyndon Johnson, Congress, and the Battle for the Great Society." He's also the co-host of the "Politics & Polls" podcast. The opinions expressed in this commentary are his own.
(CNN) - Sen. Bernie Sanders is making a big move to push for "Medicare for All." His plan would gradually expand the health care plan originally enacted in Lyndon Johnson's presidency, with new portions of the population being brought in incrementally over a four-year period. The legislation has 15 co-sponsors, including some high-profile Democrats like Elizabeth Warren, Kamala Harris and Cory Booker, who believe this is the best solution to our nation's health care problems.
Critics within the Democratic Party are warning that this is a move in the wrong direction.The party would be latching onto an idea that is far too radical. It would alienate moderate voters who don't want bigger government and stimulate fierce opposition that would make the tea party look like kid's play.
But the critics are wrong. Medicare for All could be a winning political issue for the party. It does not need to turn out like the Republican's failed attempts at "repeal and replace."
The most important contribution that Sanders' plan would make is to offer Democrats a clear and compelling idea to fight for at a time that the party has seemed aimless -- other than in its hatred of President Donald Trump. After too many years of small ball, Sanders's proposal would offer Democratic officials and candidates the opportunity to think big and to show that they have a concrete vision for making the lives of working-class Americans better.
Providing cheaper and more accessible insurance is something that many people in this country want. The plan moves the system to a government-run, single-payer program.
To the skeptics who warn that a plan for bigger government is a political death trap for Democrats, it would be worth revisiting how the repeal-and-replace struggle played out for the GOP. The key stumbling block for the party's recent efforts to gut the Affordable Care Act was the fact that the plan to withdraw Medicaid benefits was deeply unpopular, as was the possibility of denying coverage to Americans who had been protected under other parts of ACA.
When it comes to health care, there is ample evidence that voters are open to more federal support -- not less -- particularly when it comes to assisting vulnerable segments of the population. Republicans saw this first hand; Democrats need the courage to see this as well.
And Medicare for All is powerful because it builds on a program that millions of Americans are familiar with. Families across the country, in states red and blue, depend on Medicare or have family and friends receiving benefits from the coverage.
Some in the health care industry also know why Medicare is a good thing. Hospitals and doctors count on these federal dollars. In 2015, Medicare constituted 20% of national health care spending, including 23% of doctor's bills and 25% of hospital coverage.
Sanders' plan makes the politically attractive move of expanding an existing and largely successful policy, rather than starting something new. This was the reason that Medicare supporters built their program into Social Security in 1965, a benefits program which was enormously popular at the time. Making Medicare part of Social Security helped Johnson's plan get off to a head start and gave policymakers some political wiggle room to make sure that the program ran well.
While there are many questions about how the program should be structured so that it is most effective, that is not a reason to back down. The limits of providing health care through complex regulations and subsidies has become clear after our experience with ACA.
What seems to work best, and what many voters seem to like most, is when the government steps in and helps. And many economists agree. Princeton economist Uwe Reinhardt has argued that Medicare has been an efficient program and provided a solid foundation to build upon. When it comes to providing insurance, as proponents of the public option argued back in 2009, the government has actually done a pretty good job.
Of course, if there is agreement on principle, there will be problems in an actual debate over the plan. The details will matter. Most important will be cost. Proponents will have to demonstrate how the higher taxes required to pay for the plan would balance out the rising premiums under the current status quo -- or the plan proposed by Republicans with repeal and replace.
Sanders and his allies will also have to consider what kinds of out of pocket costs to require of beneficiaries -- just as the designers of Medicare originally required the beneficiaries of Part B to make contributions -- in order to curtail the cost to Treasury.
Moreover, proponents will have to be ready for opposition from the health care industry, which may fear that the government will regulate how much they charge for medical services once the government is footing a larger portion of the bill.
Proponents should be armed with some historical reminders about how the top opponents of Medicare -- doctors -- ended up benefiting from more Americans having insurance.
For too long, Democrats have been scared of their own principles, always working within the parameters of political debate set up by Ronald Reagan. Right now, Sanders is giving them a chance move in a different direction and with a concrete health care plan that could expand affordable coverage to millions of Americans.