Donald Trump spent Tuesday campaigning to repeal Obamacare, promising to replace it with something much better — a dubious claim at best.

"If we don't repeal and replace Obamacare, we will destroy American health care forever,” Trump said at his Pennsylvania rally.

He called the law a “catastrophe” and lamented how deductibles could go “up to $15,000.” Meanwhile, he promised to deliver “quality, reliable, affordable health care” — and followed up with this tweet Wednesday morning.

I am going to repeal and replace ObamaCare. We will have MUCH less expensive and MUCH better healthcare. With Hillary, costs will triple! — Donald J. Trump (@realDonaldTrump) November 2, 2016

It is true that Obamacare premiums are rising sharply this year, which threatens to make the plan unaffordable for some Americans.

But it’s also true that Trump’s health plan, which he released last March, would not fix the problem. If anything, experts say his plan would make health care much less accessible and reliable. By one estimate, Trumpcare would cause 21 million Americans to lose coverage and cost hundreds of billions of dollars more than President Barack Obama’s Affordable Care Act.

Trump has spent the campaign season promising that his health plan would cover everyone, touting these claims from the Republican debates up through this week. But it is important to remember that Trump does have a policy proposal; he has named what he would do to replace Obamacare. And it falls very, very short of his campaign trail promises.

Trumpcare would cost more than Obamacare — and cover fewer people

The biggest policy proposal in Trump's health care plan is the repeal of Obamacare. Importantly, this allows insurance companies to charge sick patients exceptionally high premiums or refuse to cover them — two practices the Affordable Care Act prohibits.

An Obamacare repeal would shrink Medicaid to cover a smaller population and eliminate the federal marketplaces where 10.4 million Americans currently purchase coverage.

Taken together, these changes would result in 22 million people losing insurance, the Center for a Responsible Federal Budget estimates.

About a million of those who lose Obamacare would gain insurance through Trump's proposal to allow insurance plans to sell across state lines. That would, theoretically, allow shoppers in highly regulated markets to gain access to less expensive coverage. (The Upshot's Margot Sanger-Katz has a good summary of this part of the Trump plan.)

Obamacare doesn't offer universal coverage. The Center for a Responsible Federal Budget (using Congressional Budget Office figures) estimates that in 2018, the Affordable Care Act will leave 27 million people uncovered. Still, Obamacare outperforms Trumpcare by a lot, because Trumpcare would add 21 million to that group, for a grand total of 48 million uninsured Americans.

Because even with the sale of insurance across state lines, Trump's plan would leave 21 million Americans without coverage.

Then there’s the cost side of Obamacare. The health law does plan to spend $1.1 trillion extending coverage to millions of Americans over the next decade. It more than offsets that spending, however, with $660 billion in new taxes and $880 billion in Medicare cuts.

This ends up making Trumpcare hundreds of billions of dollars more expensive than Obamacare. Trumpcare raises federal spending $270 billion under dynamic scoring (a model that estimates faster economic growth due to Obamacare repeal). If you use conventional scoring, which does not assume faster economic growth, the cost is $500 billion.

Trumpcare does have a few money-saving provisions, like allowing Americans to import prescription drugs from across the border. But that saves only about $20 billion — a far cry from the taxes and Medicare cuts it repeals.

Trump promises that he’ll “cover everybody.” But his plan doesn’t do that.

Donald Trump has repeatedly promised — on debate stages and in interviews — that his health care plan would cover "everybody."

"I am going to take care of everybody," Trump told 60 Minutes in an interview last fall. "I don’t care if it costs me votes or not. Everybody’s going to be taken care of much better than they’re taken care of now."

Trump’s health care plan promises that he will not “not allow people to die on the sidewalks and the streets of our country" for lack of access to health insurance.

But there's nothing in his health policy proposals — not in his seven-point plan released in March, and not in what he said at his rally in Pennsylvania — that prevents people from dying in the streets. There's no guaranteed access to insurance at all. Trumpcare, it turns out, leaves plenty of cracks for people to slip through.