States that expanded Medicaid under the Affordable Care Act have found it a major aid in confronting the painkiller epidemic.

Congress returns next week to Washington with much on its plate — not least a tight timeline to pass a spending bill to keep the government open.

But a topic that remains high on the Republican majority’s to-do list is its vow to “repeal and replace” the Affordable Care Act, aka “Obamacare.” Their first effort was a spectacular failure; it never even came to a vote in either chamber because the Republicans have no genuine alternative.

Policy matters and policy details in the complex field of health care figure to trip up the GOP on its subsequent go-arounds. Consider, as one example, Medicaid and the opioid crisis.

Many (but not all) states, including Minnesota, expanded Medicaid under the ACA. A goodly number of House Republicans insist on cutting that back as part of their repeal.

But Medicaid has been a major tool for dealing with the opioid epidemic. A report issued in the final weeks of the Obama administration showed the states that expanded Medicaid saw a drop in hospitalizations for substance abuse among uninsured patients; the states that didn’t expand Medicaid saw an increase. In West Virginia, 45 percent of all drug-assisted treatment — considered the most effective approach — is paid for by Medicaid. In Ohio, it’s almost 50 percent.

The obvious conclusion: If Congress drastically slashes Medicaid, as demanded by the House Freedom Caucus, the opioid crisis gets even worse. It’s possible the House might go that route just to get a bill through that chamber, but the Senate — only narrowly controlled by the GOP — isn’t likely to go along. Republican governors don’t want Medicaid slashed, and there are more than enough senators who agree.

The opioid crisis is not the front-burner issue in Minnesota that it is in such states as West Virginia and Ohio, but the state Department of Health says drug overdoses have passed traffic accidents as the leading cause of preventable death in this state. It’s a significant problem here, too.

The issue of opioids is just a fraction of the complexities involved in the GOP’s drive to overturn Barack Obama’s signature domestic achievement. The party’s haste to do so is bad public policy.

— Mankato Free Press, April 21