WASHINGTON — Even pleas from a Senate icon battling cancer might not be enough to move the defense authorization bill through congressional gridlock.

Senate Armed Services Committee Chairman John McCain, days after his brain cancer diagnosis, plead with Senate Democrats on Thursday to let him bring the 2018 defense policy bill to the floor.

But Senate Minority Leader Chuck Schumer, D-N.Y., respectfully would not budge for his Republican colleague from Arizona unless the GOP abandons the fast-track “reconciliation” process for their Obamacare overhaul effort. Senate Majority Leader Mitch McConnell, R-Ky., wasn’t going to budge either.

The impasse leaves the National Defense Authorization Act — which authorizes $700 billion for the Pentagon — in limbo and possibly delayed until September. For now, it’s another victim of the partisan infighting on health care that has gripped the Capitol, as Republicans seek to correct what they see as flawed government overreach and Democrats resist to protect a social safety net for the vulnerable.

With McCain’s treatment and travel plans uncertain, he and McConnell made a dramatic appeal to Schumer on the Senate floor to let the bill proceed. McCain suggested the bill, which normally takes days of procedure to advance, could be disposed of on Friday.

“There are men and women who are in harm’s way today, whose lives are in danger, who need this legislation to be better equipped and better able to defend themselves and this nation,” McCain said. “I’m asking for a few hours.”

McCain said the bill could be passed quickly, ”because we have basically an agreement on amendments and get this thing to the president’s desk so that he can protect and defend this nation.”

McCain had returned to the Capitol from Arizona on Tuesday, just days after his diagnosis, to cast a crucial vote to proceed to the health care legislation. He entered the Senate chamber to a standing ovation and delivered a rousing speech on bipartisanship. But the goodwill has showed its limits.

Two days later, Schumer, even as he touted his respect and “unbounded” love for McCain, still said no. It was reconciliation, he said, that prevents the Senate from advancing to another bill without unanimous consent.

“I must say, the reason that we must ask consent to go to the bill is we’re in reconciliation — the very process that has prevented us from debating, from having hearings, from having some kind of bipartisan input,” Schumer said.

“And I would say to my colleague, if you want to get rid of this reconciliation, fine. Let’s recommit the bill to committee and start on a fair process, and we can go to NDAA immediately, in an hour, if we were to do that,” he said.

McConnell asked in vain for consent to turn to the NDAA “to accommodate the chairman’s schedule and give him an opportunity to finish that bill while he is here.”

McCain told reporters after the floor debate that he believed Schumer understands his situation but has a Democratic Conference he is beholden to.

With the Senate due to adjourn for recess Aug. 11, the Senate could take up the NDAA next week, after health care is likely to be done. But McCain said he was not sure how long he would be in Washington.

Leo Shane III, in Washington, D.C., contributed to this report.