Over the past few months, Donald Trump has staked out an aggressive opposition to "Medicare-for-all," an increasingly popular liberal slogan that has multiple meanings but usually refers to some sort of single-payer health care system.

This is rather rich coming from a candidate who touted single-payer's virtues during the Republican presidential primaries. But Trump's opposition is not merely ironic. It is self-contradicting. The president's primary argument against Medicare-for-all is that it is a socialist scheme that would ruin Medicare, the nation's largest socialist health care program.

That contradiction is apparent in a Trump-bylined op-ed for USA Today in which the president positions himself as defender of Medicare, a $700 billion federal health care entitlement that benefits seniors. Early in the piece, he—or his ghost writer, as it is far too cogent for Trump to have written it himself—writes:

I also made a solemn promise to our great seniors to protect Medicare. That is why I am fighting so hard against the Democrats' plan that would eviscerate Medicare. Democrats have already harmed seniors by slashing Medicare by more than $800 billion over 10 years to pay for Obamacare. Likewise, Democrats would gut Medicare with their planned government takeover of American health care.

Later in the piece, Trump warns that "if Democrats win control of Congress this November, we will come dangerously closer to socialism in America. Government-run health care is just the beginning." Trump does not seem to realize, or at the very least he does not care, that Medicare, the program he swore to protect just a few paragraphs earlier, is a massive government-run health care financing program.

The pro-Medicare framing is hardly unique to Trump; Republicans have argued against expansions of government-run health care by saying they would harm Medicare for the better part of the decade. Following the passage of Obamacare, one of the most frequent Republican criticisms of the program was that it cut spending on Medicare. In the run-up to the 2012 election, Mitt Romney frequently advanced versions of this argument, attacking Barack Obama, for example, as "the only president in history who has cut Medicare for seniors." Romney insisted that only he could be counted on to "protect Medicare."

More recently, Florida's Republican governor, Rick Scott, warned that "if you want to protect Medicare, vote Republican. If you want a socialist experiment with Medicare, by all means vote Democrat." (Generally speaking, anything Scott says about Medicare should probably be given extra scrutiny, given that he once ran a health care company that, under his leadership, executed one of the biggest Medicare frauds in history. His defense is that, as CEO, he was unaware.)

There are many good reasons to oppose Medicare-for-all. By centralizing the financing of health care, it would further reduce many Americans' already limited health care options; in its strongest forms, it would be massively disruptive, requiring many people to switch health care plans; it would be incredibly expensive to the federal government—costing an estimated $32 trillion over a decade, which would require either significant tax hikes to offset or an extraordinary increase in federal debt. And that figure assumes that provider payments could be drastically reduced from current levels without reducing access to health care services, which is unlikely to be true. Practically speaking, it would be quite difficult to implement the transition from the country's current mixed public-private system.

But the notion that Medicare-for-all should be opposed because it would inject socialism into Medicare is bizarre and contradictory. Medicare is a federal program that finances health care benefits for seniors; its scope is constrained by age, but it is socialism.

As Philip Klein has argued, this framing makes it even more difficult to build support for reforms to Medicare that are absolutely necessary for our long-term fiscal stability. The position of Trump, and of much of the Republican Party, appears to be that Medicare spending can never be reduced or contained, even years in the future, because doing so would threaten seniors, a core Republican constituency. It is a position that makes Republicans the party of the Medicare status quo. Which is to say, it makes the GOP the party of partial, age-restricted socialism.

Indeed, Trump comes very close to saying exactly this in the piece, writing that "Republicans believe that a Medicare program that was created for seniors and paid for by seniors their entire lives should always be protected and preserved."

Despite popular misunderstanding, Medicare is not "paid for" by seniors over their "entire lives." It is a generational transfer program that forces younger workers to pay for health benefits for current retirees. Most of today's seniors will get far more out of the program than they put in. Meanwhile, the program is rapidly headed for insolvency; under Trump, the date in which Medicare's Hospital Insurance trust fund will deplete has moved forward to 2026. This is the status quo that Trump seeks to protect.

What Trump's pro-Medicare framing makes abundantly clear is that he does not oppose socialism in its current, age-limited form, which primarily benefits constituencies who vote Republican. Instead, he opposes the expansion of one of America's largest socialist enterprises beyond constituencies who vote heavily Republican. Trump doesn't really oppose socialism; he just wants limit any benefits it may produce to his supporters.