WASHINGTON—House Republicans released their plan to cut Medicaid spending, with the program’s defenders in the GOP appearing to win the intraparty clash over how aggressively to change the system that provides health insurance to more than 70 million low-income and disabled people.

Millions of Americans could lose health care coverage under a long-awaited proposal unveiled Sunday night by U.S. House Republicans that would slash $880 billion in federal Medicaid spending. Why it matters: States have been bracing for details on how exactly House Republicans would slash Medicaid funding,