WASHINGTON — Majority Leader Mitch McConnell decided to delay consideration of health care legislation in the Senate, after Sen. John McCain’s announced absence following surgery left Republicans short of votes on their marquee legislation.

McConnell’s decision amounted to another setback for GOP efforts, promoted by President Donald Trump, to repeal and replace “ObamaCare” after years of promises. McConnell issued his statement late Saturday not long after McCain’s office disclosed that he had undergone surgery to remove a blood clot from above his left eye, and had been advised by his doctors to stay in Arizona next week to recover.

With McConnell’s health care legislation already hanging by a thread in the Senate with no votes to spare, McCain’s absence meant it would become impossible for the majority leader to round up the votes needed to move forward with the bill next week as planned.

“While John is recovering, the Senate will continue our work on legislative items and nominations, and will defer consideration of the Better Care Act,” said McConnell, R-Ky. He did not say when he would aim to return to the health care bill.

“We wish Senator McCain a speedy recovery,” White House director of media affairs Helen Aguirre Ferre said Sunday.

Even before Saturday night’s developments, the fate of the health care legislation looked deeply uncertain in the Senate. In addition to two announced GOP “no” votes from moderate Susan Collins of Maine and conservative Rand Paul of Kentucky, there were at least a half-dozen other Republican senators who were withholding support from or expressing reservations about the bill McConnell released Thursday.

Last month McConnell had to cancel a vote on a previous version of the legislation as GOP opposition left its defeat assured. In a Senate divided 52-48 between Republicans and Democrats, McConnell can lose no more than two votes and still prevail.

The Senate bill, like legislation passed earlier by the House, repeals mandates requiring individuals to carry insurance and businesses to offer it, and unravels an expansion of the Medicaid program for the poor and disabled enacted under President Barack Obama’s law.

With the vote set for the coming week now indefinitely postponed, GOP success in its long-promised ObamaCare repeal grows all the more uncertain, despite heavy lobbying in recent days by Trump administration officials.