President Donald Trump once pledged to replace Obamacare with a system that would provide good health insurance for all Americans. His failure to devise such a plan became obvious during his first year in office, as he and the Republican Congress tried in vain to repeal the Affordable Care Act. Various alternatives were floated that would have only increased the number of Americans without health insurance.

Consequently, Americans turned against the idea of “repeal and replace,” and became wary of efforts to undermine Obamacare, especially its guarantee of access to insurance for people with pre-existing conditions. This has now turned into a big problem for Republican senators and representatives running for re-election.

In an apparent effort to help them out, Trump published an op-ed in USA Today. This was not an attempt to explain or even address the Republicans’ health-care misfires, let alone to finally reveal his once-promised health-care plan. Rather, Trump chose to attack Democrats by spinning a string of misrepresentations and falsehoods.

Democrats, Trump asserts in the piece without evidence, want to “eviscerate Medicare” and “outlaw” private health insurance in the U.S. “The new Democrats are radical socialists who want to model America’s economy after Venezuela,” he claims.

Setting aside the Venezuela whimsy, Trump seems to be under the impression that all Democrats want to enact Bernie Sanders’s plan to have “Medicare for All.” In truth, Democrats have all sorts of ideas for shoring up or strengthening the U.S. health-care system — including at least six that involve expanding Medicare eligibility or creating a public insurance option that’s based on the Medicare or Medicaid model.

Nobody ever accused Trump of being a policy wonk, and he may not understand the other party’s proposals. But it goes beyond misunderstanding to charge, as he does, that “Under the Democrats’ plan, today’s Medicare would be forced to die.”

Among the other falsehoods in the article, perhaps the most egregious is Trump’s claim that he has kept his own promise to “protect coverage for patients with pre-existing conditions.” The exact opposite is true: His administration has asked a federal judge to declare that Obamacare’s protections for pre-existing conditions are invalid, now that Congress has done away with the individual mandate (the tax penalty for going without health insurance).

Congressional Republicans are doing little better speaking for themselves. Some have introduced legislation meant to keep protections for people with pre-existing conditions in the event the Trump administration wins its argument in court. But this would not stop insurers from excluding some kinds of health-care coverage that people who are ill might need.

In any case, insurers would have difficulty accepting customers with pre-existing conditions in a system that did not also expand insurance enough to cover the cost.

The best way to avoid any further weakening of the U.S. health-care system is to embrace and improve upon Obamacare, including by reinstating the individual mandate. Voters should remain wary of any political candidate who claims that Trump or congressional Republicans have a better idea.