Donald Trump offered the single best, most original policy idea in the Republican Party debate Thursday night. He also demonstrated by far the greatest understanding of a complicated area of public policy. There, I said it.

Update: Coverage of the second Republican debate 2015.

People have been avoiding noticing this out of a dual aversion to Trump's brand of demagogic anti-immigrant politics and an excessive sense that deference is owed to the real professional politicians up on the stage.

But while I wouldn't rank Trump as one of the great health wonks of all time, his answer to a question challenging him to defend his past praise of single-payer health-care systems demonstrated a decent knowledge of the subject and an innovative and important health-care idea.

Trump's argument on single-payer

Single-payer health-care systems are ones in which the government acts as the insurance company for everyone. That's how Medicare works in the United States, and it's how the Canadian health-care system (conveniently also called Medicare) works for everyone, not just senior citizens.

"It works in Canada," said Trump, and "it works incredibly well in Scotland." He even went so far as to say that "it could have worked in a different age" in the United States but is not currently suited to our problems.

What Trump is talking about here is path dependency, and it's a reasonable point. It's one thing to set up a National Health Service in the wake of World War II. It's another thing entirely to come 75 years later and completely upend a system that is working pretty well for most people and that enormous institutions have made deep investments in. It's easy to dismiss this message when coming from Trump, but Atul Gawande has written brilliantly about path dependency in health-care reform and my colleague Sarah Kliff's masterful profile of Vermont's failed effort to build a single-payer system further underscores the concerns about path dependency.

Is the idea that a system could work well in one country but not in the US crazy? Not according to leading health wonk Uwe Reinhardt, who, like Trump, is an admirer of some foreign single-payer systems but skeptical of trying to remake the United States in their image.

Trump's great idea: a common market in health insurance

Trump then pivoted from this to a constructive suggestion about reforming health insurance in America, proposing a change that, while big enough to make a difference, is sufficiently non-revolutionary to be plausible.

"What I'd like to see," he said, "is a private system without the artificial lines around every state."

Right now, you see, health insurance is a heavily regulated industry. And it's regulated in slightly different ways by each state government. Consequently, while buyers and sellers of most products (breakfast cereal, cars, appliances, clothing) have one gigantic marketplace to participate in, buyers and sellers of health insurance have a handful of midsize markets (California, Texas, New York) and a few dozen small ones.

"I have a big company with thousands and thousands of employees," Trump observed, but "if I'm negotiating in New York or in New Jersey or in California, I have, like, one bidder. Nobody can bid."

One bidder is an exaggeration, but it's true that the number of players in any given state market tends to be small, and the problem is getting worse. The issue is especially severe in smaller states, where the overall size of the market isn't necessarily big enough to make it worth anyone's while to enter. But it's also a logistical hassle for employers who operate in multiple states, especially because states aren't real economic units. Lots of people live in New Jersey and work in Pennsylvania, or commute from Kansas to Missouri.

The other contenders had no answer to this

Obviously the big question about federalizing insurance regulation is what would the regulations say? This would have been a great issue for other candidates to grill Trump on or offer their own thoughts about. After all, if Trump is as much of a clown as everyone says, surely a serious dialogue about the issues would expose him as an empty suit.

But nobody rose to the challenge. Instead, Rand Paul offered: "News flash — the Republican Party's been fighting against a single-payer system for a decade. So I think you're on the wrong side of this if you're still arguing for a single-payer system."

This is inaccurate history — Republicans have been fighting single-payer for way longer than that — but it also reveals a failure of basic listening skills.

Nobody had any criticisms of Trump's proposal to offer, nor any praise. They just moved on.

Non-Trump policy ideas were awful

Trump's health-care suggestion, though innovative and correct, leaves a lot to be desired in terms of concrete detail.

But consider the other main policy ideas discussed:

Mike Huckabee said we could close the actuarial shortfall in Social Security by making "illegals, prostitutes, pimps, [and] drug dealers" pay taxes.

Jeb Bush said we could achieve 4 percent GDP growth by "lift[ing] our spirits and hav[ing] high, lofty expectations for this great country of ours."

Chris Christie proposed raising the Social Security retirement age, which at least makes sense but is a disaster for the poor.

Scott Walker said police officers should be trained.

Marco Rubio and Scott Walker both said we should ban abortion even in cases where abortion is necessary to save a pregnant woman's life.

Rand Paul touted his budget proposal that would be devastating to the poor.

Ben Carson doesn't have any policy ideas.

Ted Cruz promised to "open an investigation into these videos and to prosecute Planned Parenthood for any criminal violations."

John Kasich managed to get through a discussion of his Medicaid policy in Ohio without saying a single word about what he would do with Medicaid as president.

Most journalists seem inclined to give their plaudits to Kasich, who, to his credit, did give an extensive and fluent answer on a public policy question. But it was purely a question about state policy in Ohio! We learned that Kasich feels governors should accept the Medicaid expansion dollars offered under the Affordable Care Act. But as president, would he repeal the Affordable Care Act? Would he enact the further Medicaid cuts enshrined in various House GOP budget proposals?

Nobody knows.

It's time to start taking all these governors and senators seriously

An incredible quantity of pixels have been spent thus far on the question of Donald Trump and whether to take him seriously or how to understand what he represents. The reality is that he is very unlikely to win.

The next Republican nominee is almost certainly going to be Jeb Bush or Scott Walker or Marco Rubio, and if not one of them then one of those other current or former governors and senators up on the stage.

It is true that they are lagging in the polls. But there's more to life than early polls.

It's time for the press to start taking seriously the idea that the next president of the United States may very well be named Bush or Walker rather than Trump. Before that happens, inquiring minds might be interested to know what kinds of policies Bush and Walker have in mind to address national problems other than the plague of lifesaving abortions and retired 68-year-olds that afflict the fevered minds of some of these contenders.

What will the "serious" Republican candidates do to make health care and higher education more affordable? What will they do to raise wages? What will they do to address climate change or cut the poverty rate? How would they handle the insolvency of a major American bank?

Unlike the rest of the field, Trump actually addressed one of these issues, and did so in a plausible way. He seems like a buffoon, a racist, and a misogynist. But he deserves credit for taking an actual stand on policy.

Watch: Why primary debates actually matter