Instead of waging nonstop war over Obamacare, Republicans and Democrats should fix it — and a Democratic governor has ideas about how to do it.

Phil Bredesen, a former health care executive who’s finishing eight years as governor of Tennessee, saved his state from Medicaid-induced bankruptcy and emerged as a critic of the health care reform bill that his party and president pushed through Congress this year.

He’s written a book, “Fresh Medicine: How to Fix Reform and Build a Sustainable Health Care System,” that could form the basis of a bipartisan rewrite of Obamacare.

As matters now stand, Republicans plan to try to repeal the 2010 health reform law, which President Barack Obama will veto.

Then, the GOP will try to defund or otherwise block aspects of its implementation, creating more of the uncertainty that Republicans say the plan has caused for struggling businesses.

And the battle is likely to go on into and through the 2012 elections — possibly with no resolution even then.

Bredesen’s plan has aspects that should appeal to both parties. For Democrats, it’s universal and comprehensive, guaranteeing basic health care for everyone, financed through a trust fund akin to Social Security.

For Republicans, it includes vouchers, offers free choice of health care plans, replaces Medicare and Medicaid, and limits medical malpractice awards.

And, for both parties (and the country), it saves lots and lots of money — $4 trillion in the year that the plan is fully in place and $25 trillion over a 15-year implementation period, assuming health care spending is reduced from the present 17 percent of gross domestic product and capped at 14 percent.

There are controversial elements to it, for sure — a legislated ceiling on how much the plan can cost and a steeply progressive set of taxes to pay for it, including a 20 percent payroll tax up to $500,000 of income and a 10 percent income tax surcharge.

Moreover, the government would have to borrow $6 trillion to $7 trillion over 15 years to provide seed capital for the trust fund.

But Bredesen contends that, for average Americans, the taxes would cost less than they pay in lost wages for health insurance.

The borrowed money would be paid back — and the system would keep the country from going broke paying for health care.

As matters stand now, health care is projected to consume 25 percent of the national economy sometime in the 2020s — and, Bredesen told me, at best the new health care law “will bend the curve only slightly one way or another.”

He doubts it will do so. “Making it possible for tens of millions of people to have health insurance … is a very good thing, but doing it by adding them to an already unsustainable system just kicks the can down the road a bit farther.”

Bredesen agrees with many Republicans that “the fundamental problem with our health care system is that we have systematically removed the tension between buyer and seller that makes economics work.” That is, it’s not a true market system.

Patients with insurance have no idea what any procedure costs. Providers can jack up fees to the limit of an insurer’s willingness to pay. And insurers fundamentally are just intermediaries, passing costs on to employers.

In the meantime, the per capita cost of health care in the U.S. is double that of any other industrialized country, about 20 million people will remain uncovered even when Obama’s new law takes effect and the U.S. ranks 28th among developed countries in infant mortality and 16th in female life expectancy.

Bredesen wants to base reform on rigorously researching best practices, raising quality, measuring performance, telling consumers how providers rate and letting them choose which provider group they want to sign up with.

He envisions the creation of “systems of care” — the Mayo Clinic is a model — which would offer all standard plan services and take responsibility for keeping patients healthy, not just performing (and charging for) individual procedures.

Key to the program, he told me, is to “create a world of limited resources” for health care — the only way to put market forces into play in a field where costs are now “open-ended.”

“An economy does not work in a garden of Eden,” he said.

Congress would set the level of the GDP the basic program could cost and vouchers would be apportioned accordingly. Provider groups would have an incentive to keep costs down.

People seeking services not covered by the basic plan could buy them with their own money.

Bredesen thinks it will take 15 years to get his plan fully up and running — perhaps from 2016 to 2030 — but at the end of the process, “the result is the health care system we’ve been seeking — universal, fair, high quality, reasonable in its cost, honestly paid for, uniquely American.”

Instead of wrangling incessantly over the GOP demands to “repeal and replace” Obamacare and Obama’s offer to merely “tweak” it, Congress ought to reform the reform — and call Bredesen in to help.