The Supreme Court seemed likely to uphold a key preventive-care provision of the Affordable Care Act in a case heard Monday.

Conservative justices Brett Kavanaugh and Amy Coney Barrett, along with the court’s three liberals, appeared skeptical of arguments that Obamacare’s process for deciding which services must be fully covered by private insurance is unconstitutional.

The case could have big ramifications for the law’s preventive care coverage requirements for an estimated 150 million Americans. Medications and services that could be affected include statins to prevent heart disease, lung cancer screenings, HIV-prevention drugs and medication to lower the chance of breast cancer for high-risk women.