Senate Republican leaders bowed to pressure from within their own ranks Tuesday and postponed a vote to overhaul the Affordable Care Act until after the July 4 recess, raising doubts about their ability to fulfill one of their party’s core political promises.

The delay, which now exposes lawmakers to a barrage of lobbying as they face their constituents over the holiday, has left a measure orchestrated to pass swiftly this week now teetering in the balance. But, Senate Majority Leader Mitch McConnell (R-Ky.) had little choice after five Senate Republicans said they could not support a move to bring up the bill this week in the wake of a new budget analysis of the bill’s impacts.

Conservatives are blasting the plan for leaving too much of the existing law in place, while a coalition of patient advocates, doctors and senior citizens’ groups have joined Democrats in decrying its proposed cuts to the Medicaid program and rollback of taxes imposed on the wealthy.