The nation's largest physicians' group voted Tuesday to oppose any watering down or elimination of Obamacare's required minimum health coverage benefits.
The American Medical Association's move came after months of unsuccessful efforts by Republican congressional leaders to repeal and replace major parts of Obamacare.
A number of those bills would have weakened or gutted Obamacare's so-called essential health benefits.
Those EHBs cover 10 categories that health insurance plans must cover, and include emergency services, hospitalization, pregnancy and newborn care, prescription drugs, lab service and preventative care.
Republicans had considered loosening the rules around EHB coverage because doing so would have allowed insurers to charge lower premiums to customers. The EHB mandate has been blamed for driving up premium prices in the individual insurance market higher than they had been before passage of the Affordable Care Act.
The AMA said Tuesday that its opposition to any weakening of the EHB mandate was based on a report by the group's Council of Medical Service that raised concerns about the effects of such a move.
That report noted "if insurers are allowed to offer plans with skimpier coverage, plan designs could potentially discriminate against people with pre-existing conditions."
"In addition," the report said, "individuals who use services and benefits no longer included in the EHBs could face substantial increases in out-of-pocket costs."