Washington is full of arrogant people who grab power whenever they get the chance. But there is at least one modest minimalist in town, and that’s John Roberts Jr.

In his remarkable health care opinion Thursday, the chief justice of the Supreme Court restrained the power of his own institution. He decided not to use judicial power to overrule the democratic process. He decided not to provoke a potential institutional crisis.

Granted, he had to imagine a law slightly different than the one that was passed in order to get the result he wanted, but Roberts’ decision still represents a moment of Burkean minimalism and self-control.

Roberts and six colleagues also restrained the power of the federal government to sanction the states. And, perhaps most important, he restrained future congressional power.

Over the years, the commerce clause in the Constitution has been distorted beyond recognition, giving Congress power to regulate all manner of activity (or inactivity).

Roberts redefined the commerce clause in a way that limits the power of Washington. Congress is now going to have to be very careful when it tries to use the tax code and other measures to delve into areas that have, until now, been beyond its domain.

Roberts’ modest stance is generally consistent with how he has behaved over the past several years. There’s been a lot of overwrought and misleading liberal commentary on the supposed ideological activism of this court. In fact, with a couple obvious exceptions, this court has been remarkably modest.

According to a 2010 analysis by The Times, the Warren, Burger and Rehnquist courts overturned an average of nine laws a term, while the Roberts court has overturned an average of three laws a term.

And here’s the biggest gift Roberts gave to the nation: By restraining the power of the court to shape health care policy, he opened up space for the rest of us to shape that policy through the political process. By modestly refraining from rewriting health care laws himself, he has given voters and politicians more room to be audacious.

The decision doesn’t end the health care debate; it accelerates it. I spoke to some conservatives Thursday.

They were disappointed by the ruling, but they were delighted with the language on the commerce clause. Most of all, they were excited about the coming political debate. They remain sure that Obamacare is a fatally unpopular and flawed Rube Goldberg device and were energized to work harder for its repeal.

I spoke to some liberals Thursday, too. It was striking how quickly their comments moved from the past to the future — to the need to ramp up the exchanges, modernize delivery systems and build on the bundling experiments.

People in both camps seem to agree: We’ve had a big argument about health care over the past several years, yet we haven’t tackled the big issues. We haven’t tackled the end-of-life issues. We haven’t fixed the medical malpractice system. We are only beginning to correct the antiquated administrative systems.

Crucially, we haven’t addressed the structural perversities that are driving the health care system to bankruptcy. Obamacare or no Obamacare, American health care is still distorted by the fee-for-service system that rewards quantity over quality and creates a gigantic incentive for inefficiency and waste.

Obamacare or no Obamacare, the system is still distorted by the tax exclusion for employerprovided plans that prevents transparency, hides the relationship between cost and value and encourages overspending.

Liberals tend to argue that major structural changes can be made within the framework of Obamacare. Republicans tend to believe that the perverse incentives can be corrected only if we repeal Obamacare and move to a defined-benefit plan — if we get rid of the employer tax credit and give people subsidies to select their own plans within regulated markets.

Personally, I think the Republicans’ defined-contribution approach is compelling. It’s a potentially effective way to expand coverage while aligning incentives so that people make cost-conscious, responsible decisions.

But the truth is neither I nor anybody else really knows what works. We’re going to have to go through a process of discovery. We’re going to have to ride the period of rapid innovation that is now under way.

Hospitals are changing rapidly. Federal policy will change rapidly, too. The policy changes over the next decade will overshadow Obamacare.

Roberts has made a period of innovation and change more likely. He did it by taking the court off center stage and by letting the political process play out.

Self-restraint. It’s a good thing. More people should try it.

DAVID BROOKS writes for The New York Times.