America is in the middle of its worst drug crisis ever. It’s an issue that has brought together both the left and right, with figures from Barack Obama to Donald Trump calling for more to be done to fight the opioid epidemic.

Yet House Republicans just approved a health care bill that would, according to experts, make the epidemic even worse — by repealing Obamacare protections for access to drug addiction treatment. The bill now needs the Senate’s approval and Trump’s signature to become law.

The Affordable Care Act (also known as Obamacare) included 10 essential health benefits that insurers in the individual marketplace, Medicaid, Medicare, and some other health plans were required to cover. Among those 10 essential health benefits were mental health services and addiction treatment.

The American Health Care Act (AHCA), the Republican health care bill, would allow states to get waivers to this requirement — letting insurers limit the scope of what they cover, perhaps to not include mental health services and addiction treatment. This part of the bill was added after AHCA failed to gather enough support for a vote earlier this year, and it’s one of the reasons enough conservative Republicans got on board for the bill this time around for it to pass the House on Thursday.

Essential health benefits are huge for people with drug use disorders. Before, it was fairly common for insurers to leave out addiction treatment in their plans. If someone with a drug use disorder wanted to get coverage, she would typically need to find a more expensive plan that did include addiction treatment — and perhaps she wouldn’t be able to find a plan, particularly an affordable one, at all.

“Over the last 60 years, 70 years, or so, insurers have scrupulously avoided enrolling people with mental health and addictions as much as possible,” Richard Frank, a health economist at Harvard, recently told me. “That’s because they are more complicated and expensive to treat. And they did so by offering either no coverage or limited coverage.”

According to a previous analysis by Frank and Sherry Glied of New York University, these parts of Obamacare helped 2.8 million Americans with drug use disorders and nearly 1.3 million with serious mental disorders. These people would stand to lose potentially life-saving addiction and mental health coverage if essential health benefits were repealed.

This would come at a particularly hard time for America’s drug problem. Due to the opioid epidemic, drug overdose deaths have been rapidly rising for years — reaching 52,000 in 2015, an all-time record, according to federal data. If people don’t have access to adequate drug treatment, we can only expect this crisis to get worse.

Republicans have long wanted to take down essential health benefits

Even before Republicans added the waivers option to AHCA, the bill already took significant steps to weaken essential health benefits.

For one, the AHCA would repeal essential health benefits requirements for Medicaid plans, allowing states to stop covering drug treatment in Medicaid altogether. And it would weaken essential health benefits for private plans by eliminating “actuarial value” requirements that require insurers to pay for a certain amount of care — making it so insurers can effectively say that they cover, for instance, mental health and addiction care without actually paying for it.

And now they have included a waiver that would let states undo requirements for essential health benefits altogether.

Republicans have long decried Obamacare’s essential health benefits, arguing that mandating so much coverage for insurers makes health plans far too expensive. It’s true these requirements do make insurance overall more expensive, since it forces insurers to cover more stuff. But the idea is that by requiring everyone to cover these benefits, the cost is shared by the whole insured population, not just the people who need, say, drug treatment or maternity care and would otherwise have to find a way to pay for either on their own.

Republicans just don’t think the trade-off is worth it, since it makes insurance a bit more expensive for everyone.

But without these protections, people with drug use disorders will suffer as health insurance becomes much less accessible and much less comprehensive. As Jessica Goense, who obtained care at a New Jersey addiction program with the help of Obamacare-expanded Medicaid coverage, recently told me, “If it wasn’t for insurance, I wouldn’t be here.”

Beyond essential health benefits, the AHCA also just flatly reduces access to coverage

It’s not just essential health benefits, though. The other big sticking point for drug treatment: The AHCA would do several things to reduce health coverage across the board — which would affect everyone, but particularly people who rely on coverage to get drug treatment.

Over the next few years, the AHCA would phase out the Medicaid expansion. It would pull back Obamacare’s tax credits, as well as regulations that shield older people from high premiums, effectively making insurance much more expensive for older, low-income Americans. And it would effectively cut Medicaid by moving it toward a “per capita cap” system or a block grant system that would over time give states less money for the program, on top of allowing states to peg a work requirement to Medicaid.

In total, the Congressional Budget Office estimated that the AHCA would cost 24 million Americans their health insurance by 2026. Although since the CBO’s estimate, Republican legislators have dramatically changed their bill without getting an update from the agency.

Obviously, losing access to Medicaid and other insurance would hurt a lot of people in general, removing access to any health care. But one of the forms of health care that’s affected here would be coverage for drug treatment. And that would be particularly stifling for low-income people, who simply can’t afford to pay out of pocket for this kind of care. That’s one of the reasons that, according to a 2016 report by the surgeon general, just 10 percent of the people with a drug use disorder got specialty treatment — and that was with Obamacare largely in place.

Consider Medicaid. According to a 2014 study by Truven Health Analytics researchers, Medicaid paid for about 25 percent — $7.9 billion of $31.3 billion — of projected public and private spending for drug abuse treatment in 2014. That made it the second biggest payer for drug treatment spending after all local and state government programs.

But the AHCA’s cuts to Medicaid would limit how much the program can do.

This would come on top of another existing limitation: Even if a health plan covers drug treatment, it might not cover all kinds of treatment. For example, some states include medication-assisted treatment such as methadone and buprenorphine in their Medicaid plans, while others only cover more traditional addiction therapy and treatment facilities built around the Alcoholics Anonymous approach. So it can vary from state to state and plan to plan, but generally addiction care isn’t in an ideal place even under Obamacare — and it’s likely to become more limited under the AHCA.

There’s a secondary effect, experts warn, that would further limit access to treatment: If treatment programs know or suspect they’re going to have fewer people using their services (since fewer people may have insurance), they’re probably going to be more reluctant to open up more facilities. And that could leave some areas without any options for care.

“A key issue here is that [substance use disorder] care is not like oncology or cardiology,” Keith Humphreys, a drug policy expert at Stanford University, told me. “Most providers are small, mono-business entities that can’t absorb costs elsewhere in their care systems. What this means is that while hospitals will not go broke if poor people get less oncology care coverage, many [substance use disorder] treatment agencies will.”

Given that waiting times for appointments to drug treatment facilities can already be weeks or months long, this would exacerbate an already bad problem.

So millions of Americans with drug use disorders stand to suffer under the bill — in the middle of the deadliest drug crisis in US history.