Donald Trump on Sunday called Sen. Ted Cruz a "liar" for suggesting that a vote for Trump is a vote for Obamacare. Trump is right in a sense: His vision for healthcare isn't the same as Obamacare. In fact, it would require drastically more government.

A day before the Iowa caucuses that Trump is now favored to win, ABC's George Stephanopolus asked the GOP frontrunner about his repeated statements in favor of universal healthcare. Trump said, "I want people taken care of. I have a heart. I want people taken care of. If people have no money, we have to help people. But that doesn't mean single payer. It means we have to help people. If somebody has no money and they're lying in the middle of the street and they're dying, I'm going to take care of that person —"

At that point, Stephanoplus interjected and asked how he would do it, and Trump said, "We're going to work with our hospitals. We're going to work with our doctors. We've got to do something. You can't have a — a small percentage of our economy, because they're down and out, have absolutely no protection so they end up dying from, you know, what you could have a simple procedure or even a pill. You can't do that. We'll work something out. That doesn't mean single payer. And I mean, maybe [Cruz]'s got no heart."

To start with, it's noteworthy that Trump echoed leftist rhetoric by talking about the need for government to provide health coverage by arguing that people would be dying in the streets otherwise — and framing anybody who disagreed as heartless.

But in terms of the substance (to the extent that we can discern any) the idea that Trump would replace Obamacare with a system in which government negotiated with doctors and hospitals is in fact the vision for a government-run system.

It also comes on top of Trump's long history of embracing government-run healthcare — both decades ago and during this campaign.

In his 2000 book The America We Deserve, Trump described himself as a "liberal" on healthcare and suggested the U.S. should look to Canada's socialist system as a "prototype." During a Republican presidential debate, he said the socialist systems in Canada and Scotland worked well.

During an interview on "60 Minutes," last September, Trump said, "Everybody's got to be covered. This is an un-Republican thing for me to say because a lot of times they say, 'No, no, the lower 25 percent that can't afford private.' But ... I am going to take care of everybody."

Asked how, he said, "I would make a deal with existing hospitals to take care of people." Asked who would pay for it, Trump said, "The government's gonna pay for it. But we're going to save so much money on the other side." Though he went on to add that there would be private competition, the fact that he said government would be paying to ensure healthcare for all and that they'd be negotiating directly with hospitals would mean an expanded role for the state relative to Obamacare.

And last week he called for Medicare to negotiate drug prices, a long-time liberal policy goal that's also currently being advanced by Democratic presidential candidates.

To be clear, Obamacare does not cover everybody and it does not empower government to negotiate drug prices.

The idea that government can cover everybody and save money by negotiating deals with drug makers, doctors, and hospitals doesn't just sound like single-payer. It is in fact one of the central policy arguments used by proponents of single-payer. The idea is that because government is a massive purchaser, it can throw its weight around to drive down costs — thus providing more care for less money.

Socialist Bernie Sanders, in fact, makes this argument explicitly in his $14 trillion single payer proposal. "By moving to an integrated system, the government will finally have the ability to stand up to drug companies and negotiate fair prices for the American people collectively," the Sanders proposal reads. He also, like Trump, argues that under Obamacare too many people are still uninsured and struggling to pay insurance premiums.

In reality, of course, fixing prices on drugs, hospital treatment, and doctors' visits is a good way to stifle innovation, reduce competition, increase waiting times and reduce quality. Trump no doubt would argue that the magic pixie dust of his sheer awesomeness would overcome this reality, but it doesn't change the nature of what he's arguing.

So, to sum up: Trump has offered scant details about how he would replace Obamacare. But what little he has said is philisophically consistent with the arguments in favor of single-payer, a policy approach that he has praised in the past.

The whole irony of this is that right now, Sanders and Hillary Clinton are in the midst of a heated debate in which Sanders is arguing in favor of single-payer and Clinton is saying it would go too far to be politically feasible.

Should Clinton and Trump be the nominees, it will have meant that Democratic voters will have rejected the candidate pushing single-payer healthcare and Republicans will have embraced him.