If Donald Trump and Elizabeth Warren agree on something, it must be a bad idea. Yet President Trump is pushing for a one-year cap on credit card interest rates at 10%, and Senator Warren is practically doing cartwheels in support. She’s even boasted about phone calls with Trump to hammer out the details, offering to team up on legislation that would supposedly stick it to the big banks and save everyday Americans from “usurious” rates.

It’s the kind of bipartisan, populist kumbaya that is supposed to warm the heart—until you remember that government price controls have about the same long-term success rate as a Ponzi scheme.

Trump proposes a temporary credit card rate cut from their current averages around 20-25% down to 10%. Warren, who has been crusading against high interest for years, sees it as a win for consumers drowning in record-high credit card debt—over $1.1 trillion last year. Even Bernie Sanders is praising the idea. On the surface, who wouldn’t love cheaper borrowing? It’s like promising free ice cream without the calories.

But there are always calories.

Capping rates sounds benevolent, but it ignores basic economics. Credit card lenders aren’t charities; they price for default risks. High rates exist to compensate for the folks who max out their cards on impulse buys and then ghost the payments. Impose a 10% ceiling, and banks won’t suddenly become altruists—they’ll simply tighten the credit spigot. Subprime borrowers will be the first to feel it: young families, low-income workers, and people trying to build their credit will see approvals drop, credit limits shrink, and access evaporate.  Meanwhile, expect a surge in back-door costs: higher annual fees, steeper late charges, and new penalties designed to recoup losses.

Trump’s one-year “temporary” fix is especially cynical. It’s a teaser rate on steroids—encouraging folks to borrow more today, only to hammer them when the cap expires and rates snap back.

Of course, I suppose the government could try to step in further to protect lenders from losses. But if healthcare and college tuition are any guide, this kind of intervention tends to increase costs even more.

Warren frames this as a battle against “greedy” corporations. In reality, it’s a populist band-aid on a deeper, self-inflicted wound. Inflation from prior policies jacked up both consumer prices and interest rates. Slapping a cap on borrowing costs doesn’t fix underlying spending habits or fiscal irresponsibility—it just hides them for a while.

The nice thing about price controls is they feel like action. The bad thing about price controls is that they mostly just move the problem somewhere else, where it becomes harder to see but much easier to blame on someone new.

David Moon is president of Moon Capital Management. A version of this piece originally appeared in the USA TODAY NETWORK.