Congress is poised to force the Pentagon to end the military's vaccine mandate under compromise legislation to authorize funding for the Defense Department, a major capitulation for Democrats who had championed the policy despite sharp controversy in the ranks over its implementation.

The bill "requires the Secretary of Defense to rescind the mandate that members of the Armed Forces be vaccinated against COVID-19," according to a summary of the bill that Republican and Democratic leaders of the House and Senate armed services committees released late Tuesday night.

The vaccine mandate became a centerpiece of recent negotiations after Republicans threatened to prevent passage of the annual defense authorization bill as a standalone measure if the measure was not stripped from it. Congress has maintained the tradition of passing a bill to authorize defense spending for six decades running, even as it has dropped the ball on authorizing other parts of the federal budget.

The move appears to undercut what Defense Secretary Lloyd Austin had been advocating.

"Secretary Austin supports maintaining the vaccine mandate," Pentagon press secretary Brig. Gen. Patrick Ryder said in a statement on Monday. "The health and readiness of our forces is critical to our warfighting capability and a top priority."