Senate Republicans have found a new enemy in America’s opioid epidemic: Medicaid.

On Wednesday, the Senate Homeland Security and Governmental Affairs Committee, led by Sen. Ron Johnson (R-WI), will hold a hearing focused on the impact of Medicaid on the opioid epidemic. Along with the hearing, Johnson also released a report and an op-ed that attempt to blame Medicaid — and the Medicaid expansion funded by the Affordable Care Act (“Obamacare”) — for at least part of the growth in drug overdose deaths over the past several years.

The basic argument: Medicaid, particularly through the Obamacare-funded expansion, gave patients greater access to opioid painkillers — by linking them to doctors who could prescribe the drugs and by paying for many of the pills. Patients then misused the opioids, shared the drugs with others, or sold them on the black market. That, the claim goes, fueled the current drug overdose crisis, which led to nearly 64,000 overdose deaths in 2016.

This is not a new argument. During the debate over Obamacare repeal, some Republicans raised this claim as part of their rationale for pulling back the health care law’s insurance expansion. Online, this argument has gained more traction due to wider discussion in the blogosphere and social media.

But this claim runs into a basic problem: the concept of time. Medicaid didn’t expand under Obamacare until 2014 — well after opioid overdose deaths started rising (in the late 1990s), after the Centers for Disease Control and Prevention in 2011 declared the crisis an epidemic, and as the crisis became more about illicit opioids, such as heroin and fentanyl, rather than conventional opioid painkillers.

“It’s pretty ridiculous,” Andrew Kolodny, an opioid policy expert at Brandeis University who’s scheduled to testify at the Senate hearing, told me.

Yet the claim has persisted, wrapped in the broader context of Republicans trying to cut Medicaid. During 2017’s Obamacare repeal efforts, Republicans proposed cutting the program and undoing the Medicaid expansion. Recently, President Donald Trump’s administration and Republican state leaders have moved to tie work requirements to Medicaid. And congressional Republicans have publicly discussed passing entitlement reforms — which would cut Medicaid, among other federal programs — at some point in 2018. This has long been a goal of Republicans, who claim Medicaid is too expensive and removes an incentive to work (by letting people get insurance without a job).

Other evidence, meanwhile, suggests that Medicaid could actually act as a solution to the opioid crisis — because Medicaid, by expanding access to addiction treatment, could help stem the tide of addiction and overdose deaths. So by using this new hearing and report to potentially attack Medicaid, Republicans may be in fact undermining a potential solution to the overdose crisis.

The faulty reasoning behind Senate Republicans’ opioid-Medicaid hearing

The origins of the theorized link between Medicaid and the opioid epidemic appear to be a passage from Dreamland: The True Tale of America’s Opiate Epidemic, a 2015 book by Sam Quinones: “For a three-dollar Medicaid co-pay, therefore, addicts got pills priced at thousands of dollars, with the difference paid for by U.S. and state taxpayers. A user could turn around and sell those pills, obtained for that three-dollar co-pay, for as much as ten thousand dollars on the street.”

Conservative pundits and policymakers, including Senate Republicans’ report, have latched onto this kind of anecdote. They also claim there’s a correlation between states that expanded Medicaid and higher drug overdose death rates, and point out that people who receive Medicaid appear to fill out more opioid prescriptions than people who are privately insured.

“In 2015, the seven states with the highest drug-overdose death rates were West Virginia, New Hampshire, Kentucky, Ohio, Rhode Island, Pennsylvania, and Massachusetts,” Sam Adolphsen, who is scheduled to testify at the Senate hearing, wrote in National Review. “These states all have something else in common: All were among the 31 states (not including D.C.) that expanded Medicaid through Obamacare.”

Researchers, however, have put this supposed link through a more rigorous scientific analysis than the pundits and policymakers have — and they’ve concluded that there’s no good evidence to suggest that the Medicaid expansion led to higher drug overdose death rates.

The best review of the evidence is a 2017 Health Affairs report by Andrew Goodman-Bacon and Emma Sandoe. They concluded:

First, trends in opioid deaths nationally and by Medicaid expansion status predate the [Affordable Care Act]. Second, counties with the largest coverage gains actually experienced smaller increases in drug-related mortality than counties with smaller coverage gains. Third, the fact that Medicaid recipients fill more opioid prescriptions than non-recipients largely reflects greater levels of disability and chronic illness in the populations that Medicaid serves.

Take a look at the following chart by Goodman-Bacon and Sandoe. It shows that the states that would go on to expand Medicaid saw a divergence in drug overdose deaths compared to non-expansion states before the Obamacare expansion began in 2014. If the expansion caused the divergence, this chronology would simply not be possible.

This chart, instead, supports the opposite conclusion that Republicans are drawing from the correlation. As Kolodny told me, “The only explanation I can come up with if there really is this association is that states hit hardest by the opioid crisis were more likely to expand Medicaid perhaps because they were dealing with a very expensive [opioid] problem.”

There’s another basic time problem with the Republican theory: The nature of the opioid crisis has, if anything, shifted away from opioid painkillers since the Medicaid expansion began. Starting around 2011, opioid painkiller overdose deaths began to level off. That same year, heroin overdose death began to rise. Then in 2014, overdose deaths linked to synthetic opioids like illicit fentanyl began to rapidly increase as well — and now these synthetic opioids are the biggest cause of overdose death in the US.

Research tells a similar story: A 2017 study in Addictive Behaviors found that 51.9 percent of people entering treatment for opioid use disorder in 2015 started with prescription drugs, down from 84.7 percent in 2005. And 33.3 percent initiated with heroin in 2015, up from 8.7 percent in 2005.

This simply doesn’t gel with the theory that the Medicaid expansion fueled the opioid crisis. If the theory held up, we would expect to see a dramatic rise in opioid painkiller addiction and overdose deaths since 2014, because those were the drugs that new Medicaid patients would now have access to. Instead, the painkiller problem seems to have by and large leveled off while other opioids have become much bigger concerns. (That’s not to say opioid painkiller addiction is no longer a problem, but it’s not the rapidly growing calamity it once was.)

The Senate Republican report also goes beyond pointing to the above correlations, touting evidence of people defrauding Medicaid to obtain opioid painkillers: “At least 1,072 people have been convicted or charged nationwide since 2010 for improperly using Medicaid to obtain prescription opioids, some of which were then resold on the nation’s streets. The number of criminal defendants increased 18 percent in the four years after Medicaid expanded, 2014-2017, compared to the four years prior to Medicaid expansion.”

This correlation, though, doesn’t necessarily give evidence for more crimes; it could also be evidence that law enforcement is now taking these types of crimes more seriously. For example, Obamacare allocated $350 million for health care fraud prevention and enforcement. As the opioid epidemic has received more attention, it’s not surprising that law enforcement would use these and other resources to go after crimes linked to the crisis.

Senate Republicans are singling out Medicaid for what the whole health care system got wrong

Now, it is true that Medicaid has generally paid for more opioid prescriptions since the 1990s. And some of those opioids were diverted to misuse and trafficking, as Quinones reported.

But this was true for all health insurers. In the 1990s, private insurers also got swept up in paying for more painkillers as doctors prescribed way more of the drugs (in large part due to a misleading marketing push from major drug companies suggesting, incorrectly, that opioids were safe and effective). Private insurers, like Medicaid, also often paid for these painkillers with little to no cost to the patient. And the patients, like those on Medicaid, sometimes shared or sold their extra pills.

It’s through this embrace of opioids by the whole health care system — from insurers to doctors to drug companies — that the US became by far the world’s biggest consumer of opioids, causing the pills to proliferate to people with pain, teens rummaging through parents’ medicine cabinets, and the black market. (More on the causes in Vox’s opioid epidemic explainer.)

Some previous data does suggest that Medicaid recipients receive opioid prescriptions twice as often as non-recipients.

But to the extent this is still true, Goodman-Bacon and Sandoe’s analysis concluded that it’s likely due to differences in health care needs: “Medicaid patients, especially those who qualify through a disability and many who do not, are more likely to have chronic conditions and comorbidities that require pain relief. Between 2010 and 2016, 30 percent of Medicaid recipients ages 25-54 reported having pain most days or every day, compared to 14 percent of non-recipients.” (Remember: One cause for Medicaid eligibility is a severe disability.)

So blaming Medicaid for this problem unfairly singles out one program for what was really a broader systemic issue in the health care system.

Medicaid is part of the solution to the opioid crisis

The reality, according to drug policy and public health experts, is that Medicaid could actually play a role in ending the opioid crisis.

That’s because Medicaid can help pay for addiction treatment, including highly effective medications, such as buprenorphine and methadone, that are considered the gold standard treatment for opioid addiction.

This is already true to some extent: 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 addiction treatment in 2014. That made it the second-biggest payer for drug addiction treatment spending after all local and state government programs.

Some places have also leveraged Medicaid dollars in innovative ways. Vermont, for example, has built a “hub and spoke” system that treats addiction as a public health issue and integrates treatment into the rest of health care. Obamacare and Medicaid were crucial to this: The state obtained a special Medicaid waiver through the federal health care law to help fund the program, and it continues paying for treatment services largely through insurance payments from patients who are often insured thanks to Obamacare’s insurance expansion.

Now, Medicaid and expanding access to insurance won’t solve every problem. Even when people have insurance, they can face other hurdles to treatment, such as high out-of-pocket costs, long waiting periods, or even a total dearth of treatment facilities in their area. That’s why experts like Kolodny argue that the US needs to spend tens of billions of dollars to rapidly scale up treatment across the country; otherwise, people may have insurance, but they won’t have access to treatment that they can actually use that insurance for.

But even if it’s not a perfect fix, Medicaid could at least help give some people greater access to addiction treatment.

Given the evidence, Kolodny argued that the new hearing and report are really about a broader Republican agenda to cut Medicaid. After all, this is something that Republicans have been trying to do for years; as House Speaker Paul Ryan once said, he’s been “dreaming” of cutting Medicaid since he and his buddies were “drinking out of kegs.”

“People are using the opioid addiction epidemic to further their own political agenda,” Kolodny said. “That bothers me. I think it becomes a distraction.”