President Joe Biden wants Medicare and Medicaid to cover weight loss drugs, a proposal that would expand access to the costly but life-changing medications for millions of people who struggle with obesity. It’s a good idea that Donald Trump should pursue when he’s in office.

Medicare, which provides health care for more than 65 million seniors, is statutorily prohibited from covering weight loss medications. Two decades ago, when Congress created the Part D benefit that pays for prescription drugs, obesity wasn’t yet recognized as a disease. Some of the weight loss drugs on the market weren’t very effective, and others were dangerous.

Today, obesity is more commonly understood to be a chronic condition that affects more than 40% of the U.S. population. Medicaid, for its part, is already allowed to cover weight loss drugs; Biden wants to require it.

The potential benefits of coverage are immense. Obesity is a risk factor in many of the nation’s leading causes of death, including heart disease, diabetes and certain cancers. So-called GLP-1 drugs, first approved for diabetes in 2005, have become remarkably effective treatments for weight loss. They’ve also been shown to reduce the risk of heart attack, stroke and kidney disease, while researchers are investigating their potential to treat Alzheimer’s and addiction, among other conditions.

Biden’s proposal, worthy as it is, faces two challenges.

The first is cost. Novo Nordisk A/S’s Wegovy and Eli Lilly & Co.’s Zepbound, two of the most effective drugs on the market, can retail for more than $1,000 a month. Though state Medicaid programs receive substantial discounts, most have balked at the potential expense. (GLP-1s need to be taken indefinitely.) Biden officials estimate that the plan, which would extend coverage to more than 7 million people, would increase federal spending by $36 billion over 10 years, net of rebates. States would be on the hook for $4 billion.

The other issue is procedural: Biden instructed the Centers for Medicare and Medicaid Services to “reinterpret” the 2003 statute prohibiting coverage of weight loss drugs “in recognition of the prevailing medical consensus that obesity is a disease.” Robert F. Kennedy Jr., Trump’s nominee for health secretary and a critic of weight loss medications, may not agree. Assuming he gets on board, rulemaking could be tortuous and subject to legal challenges.

Neither problem should be a deal-breaker. For starters, it’s plausible that the wide-ranging health benefits of weight loss drugs could offset the costs long-term. Medicare’s annual health care spending for beneficiaries with the most severe category of obesity is roughly double the level of those who are of normal weight. But while savings estimates vary widely — partly because the drugs are so new and more studies must be done — several variables could improve those forecasts, including expanded eligibility, as well as increased effectiveness and adherence. Many people stop taking GLP-1s because they’re simply unaffordable.

In the short run, a lower price is clearly needed. Germany pays about a tenth of the U.S. price for Wegovy; the U.K., even less. Like most rich countries, the U.S. has started negotiating prices with drugmakers for certain prescriptions covered by Medicare. Many expect Ozempic, Novo Nordisk’s diabetes treatment that has the same active ingredient as Wegovy, will be on the list next year. Trump should encourage these deals to continue while retaining appropriate protections for the stream of innovators entering the market that will be exempt from negotiations under certain conditions. The administration should also consider incorporating other countries’ prices in its dealmaking.

Finally, Congress should pass proposed legislation that would authorize coverage of weight loss drugs for Medicare beneficiaries with obesity and certain beneficiaries classified as overweight. The proposal would also expand access to clinicians who can provide behavioral therapy, as medication alone is unlikely to be sufficient. Diet and exercise likewise must remain central to the obesity battle.

If Trump wants to improve Americans’ health, as he says, expanding coverage of weight loss drugs should be a priority. With better prices, and support from Congress, adopting Biden’s proposal will save money and lives.