At the Rose Garden victory press conference following the House’s passage of the American Health Care Act, Donald Trump precisely explained the political conundrum Republicans now face.

“I'm telling you, no matter where I went,” he said, “people were suffering so badly with the ravages of Obamacare.” But thanks to AHCA, he promised, people will see relief.

“Your premiums,” he said, “they're going to start to come down.”

Back in the bad old days of the Affordable Care Act, “when it comes to deductibles they were so ridiculous that nobody got to use their current plan.”

But, Trump insisted, help is on the way. “Make no mistake about it,” he said, “make no mistake. I think most importantly, yes, premiums will be coming down. Yes, deductibles will be coming down.”

People who believe Tump claims are in for a rude awakening.

None of this is true

Obviously if congress passes a law and then President Trump signs it and after that the typical American finds his health insurance premiums fall even as his insurance coverage becomes more robust — with lower deductibles — then the AHCA is going to be be a huge political success.

Even more important than that, it will be a huge substantive success! Delivering cheaper premiums combined with more robust coverage would be an enormous blessing to an enormous number of people.

But the AHCA doesn’t do either of those things. After all, how could it? The heart of the bill is a $600 billion tax cut for affluent households and health industry corporations. The bill contains no reforms to the American health care payment or delivery systems. All it does is shift money around, largely by taking it away from subsidizing health coverage for older, sicker, and poorer people and plowing it into tax cuts.

The inevitable result is that millions of people will lose their insurance entirely, and those who remain will end up on average paying more for skimpier coverage.

But it gets worse

One of the political consequences of the Affordable Care Act’s passage in 2010 is that Republicans made Democrats own all future bad news about American health care, whether or not it had anything to do with Obamacare.

Most people in 2017, after all, get their health insurance through their employer just like most people did before Obama’s inauguration. And since that time, most of us have experienced rising premiums and deductibles. Not because of anything in the Affordable Care Act but because the underlying price of health care services has been growing faster than the overall pace of American economic growth for decades. If anything, cost growth since ACA’s signing has been slower than the historical trend — an achievement for which its authors probably deserve at least a little credit.

But nobody wins a popularity contest by talking about a slowing rate of cost growth relative to a preexisting baseline. The fact of the matter is that rising premiums and deductibles have caused hardship for millions of people. Voters were hoping Obama would make the health care situation better, but the situation got worse.

Trump’s irresponsible promises of lower premiums and lower deductibles aren’t in any way restricted to any particular class of people. He’s promising them to the entire American public — even though his legislation has absolutely no provisions that would deliver them.

Overpromising is great politics until it isn’t

Donald Trump’s willingness to engage in wild overpromising was probably an asset on the campaign trail in 2016.

There’s a reason that Barack Obama turned “yes, we can” into a slogan even though the practical reality of policymaking is often that “no, we can’t.” The idea that a political outsider, successful in other fields, could come to Washington and just make things generally better in a non-specific way resonated with many people — especially those inclined to share his broad cultural and racial sensibilities.

The problem is that once you’re actually governing you need to worry about what your policies actually accomplish. Whether AHCA passes or not, the general trend toward higher premiums and deductibles is going to continue in for the foreseeable future. If AHCA passes, the trend will tend to accelerate rather than slow.

And people will be angry — and rightly so — that the president broke his promises to them.