In his recent speech on health care, President Trump highlighted a proposed rule that hospitals make their prices public. It’s time for hospitals to comply. Transparency will likely lead to lower prices and a reduction in health care spending.

Many policy experts dismiss the importance of price transparency in health care. Skeptics argue that because health insurance insulates patients from prices, patients have little incentive to seek out the cheapest provider. These critics also cite studies showing that few patients use price transparency tools and that minimal savings result. On both these points, they are right. But their analysis is incomplete.

One item on voters’ short list for congressional action is addressing the growing problem of surprise medical bills.

Insured patients should be confident that if they receive care at a facility that is in their health plan’s network or have a medical emergency, they will be responsible only for their share of the plan’s negotiated rates.

But all too often, a patient receives a bill afterward from an anesthesiologist, for example, that wasn’t “in network.” The insurer says the charge isn’t its responsibility, and the patient is on the hook—often for thousands or tens of thousands of dollars.

Sen. Mark Warner, D-Va., authored the resolution, which would curtail an administration initiative that was the driving force behind the first-ever reduction in average Obamacare premiums: the authority to grant states waivers from certain regulatory requirements in the Affordable Care Act.