WASHINGTON — The Republican campaign to roll back Barack Obama’s health care law is colliding with America’s opioid epidemic.

Medicaid cutbacks would hit hard in states deeply affected by the addiction crisis and struggling to turn the corner, according to state data and concerned lawmakers in both parties.

The central issue is that the House health care bill would phase out “Obamacare’s” expanded Medicaid, which allows states to provide federally backed insurance to low-income adults previously not eligible.

Many people in that demographic are in their 20s and 30s and dealing with opioid addiction. Dollars from Washington have allowed states to boost their response to the crisis, paying for medication, counseling, therapy and other services.

According to data compiled by The Associated Press, Medicaid expansion accounted for 61 percent of total Medicaid spending on substance abuse treatment in Kentucky, 47 percent in West Virginia, 56 percent in Michigan, 59 percent in Maryland, and 31 percent in Rhode Island. In Ohio, the expansion accounted for 43 percent of Medicaid spending in 2016 on behavioral health, a category that includes mental health and substance abuse.

Those states accepted the Medicaid expansion and represent a cross-section of places hardest hit by the nation’s drug-overdose epidemic, which claimed more than 52,000 lives in 2015. Of the deaths, more than 6 in 10 were due to opioids, from prescription pain relievers like oxycodone to street drugs like heroin and an elephant tranquilizer.

Tracy Plouck, Ohio’s director of mental health and addiction services, said Medicaid expansion dollars from Washington have allowed her state to redirect its own resources to priorities like providing recovery housing after detox.

Reversing that would have real consequences for people who are trying to straighten their out their lives, she said. “If you go back into an environment where people are using, that sets you up with a risk that’s nearly insurmountable.”