Handing Mitch McConnell his biggest legislative defeat since he became majority leader this year, senators voted down all of the Kentuckian’s amendments to Patriot Act reauthorization legislation.

McConnell, who had repeatedly criticized the underlying bill, had said the amendments were crucial to preserving national security. More than a dozen Republicans voted against at least one of the amendments.

The Senate then cleared 67-32 the USA Freedom Act (HR 2048), which would set limits on the National Security Agency’s ability to review Americans’ phone records. McConnell had said repeatedly that the bill would not work, would put the United States at risk of terrorist attacks and would pose a greater risk to personal privacy than the NSA program did.

The NSA’s authority to hold Americans’ phone records expired June 1. The new legislation would require the agency to go to the phone companies, with a warrant, when it wants to review those records in the future.

McConnell has taken his lumps as leader, notably the veto of legislation to authorize construction of the Keystone XL oil pipeline and repeated defeats in his attempts to block President Barack Obama’s plan to grant legal status to more illegal immigrants — but none of those issues was his the way the Patriot Act (PL 107-56) reauthorization has been.

When McConnell in April introduced a bill (S 1035) to extend the Patriot Act provisions that undergird the NSA’s surveillance authorities for five years without changing them, it seemed tone-deaf. The security hawks in Congress have been losing ground for some time to an alliance of Democrats and libertarian Republicans who argue post-Sept. 11 surveillance programs went too far in impinging civil liberties. Last year, after all, 58 senators had voted for a bill to overhaul the authorities, and a week after McConnell made his opening gambit, the House Judiciary Committee approved 25-2 the revised authorities the Senate passed today. Two weeks after that, the House passed the USA Freedom Act, 338-88.

But amid the growing criticism of the NSA, McConnell persisted, insisting that NSA surveillance was effective and didn’t violate civil liberties. “Not only have these tools kept us safe,” he said in May, a week prior to the House vote, “there has not been a single incident — not one — of an intentional abuse of them.”

With Republicans now in charge of the Senate, McConnell figured he could at least force a compromise with the House. Only four Republican senators voted for the overhaul bill when it came up in November 2014 — Ted Cruz of Texas, Dean Heller of Nevada, Mike Lee of Utah and Lisa Murkowski of Alaska — and if McConnell could stem any further losses, the House would be forced to negotiate.

However, McConnell underestimated the willingness of opponents of any extension of the Patriot Act, led by his fellow Kentucky Republican Rand Paul, to slow the Senate’s work, and he left himself little time to promote alternatives. Hours before the Senate planned to leave for its Memorial Day recess on May 22, it was still debating trade legislation that was not time-sensitive. By pushing votes on the Patriot Act to the eleventh hour, McConnell believed senators would give him a temporary extension to work out a compromise more to his liking. But he’d already given up on his hopes of a five year extension. Instead, he lobbied Republicans to vote no on the House bill and, when it failed, he asked for a two-month extension. He said a compromise was in the works, to “improve the version that the Senate has not accepted that the House sent over. It would allow the committee to work on this bill, refine it, and bring it before us for consideration.”

But the patience of libertarian-leaning Republicans was wearing thin and their strength growing. While four Republicans had voted for the USA Freedom Act in 2014, 12 did on May 23. Four were newly elected senators, Steve Daines of Montana, Cory Gardner of Colorado, James Lankford of Oklahoma and Dan Sullivan of Alaska. More alarming for McConnell, four others had voted no in 2014 but voted yes in May, despite McConnell’s entreaties: Jeff Flake of Arizona, John Hoeven of North Dakota, Ron Johnson of Wisconsin and Tim Scott of South Carolina.

When the two month extension (S 1357) came up for a vote, only 45 senators voted aye, and two more Republicans joined the list of those willing to cross McConnell: Michael D. Crapo of Idaho and Jerry Moran of Kansas voted no.

By the time senators returned to Washington a week later, McConnell opened the floodgates, asking senators to vote for cloture on the House bill he had so strenuously opposed. Given Paul’s opposition to short term extensions, and the overwhelming Senate vote against his two month delay, McConnell said he saw no other choice. But his arguments against the House bill – particularly his repeated point that it included no requirement that the telecommunications companies retain customer calling records—made it tougher later to convince senators to vote for amendments that also included no such requirement. His refusal to allow other senators a chance to offer their own amendments also cost good will.

Senate Democrats fixated on McConnell’s amendment to eliminate a requirement in the bill that the Foreign Intelligence Surveillance Court, which grants warrants in terrorism cases in secret, empanel privacy and civil liberties experts to argue against the government position before the court. They argued it was aimed at weakening the bill’s civil liberties protections. And their position was strengthened when House Judiciary Committee sponsors of the bill, both Republican and Democrat, said it was a poison pill.

The ill will left little hope for McConnell’s amendment requiring that the Director of National Intelligence certify that the phone company databases were searchable in real time before the transition from NSA storage of the call records to phone company stewardship could be finalized. That struck civil liberties advocates, and their allies in Congress, as a way to stop the bill’s main provision, ending government storage of Americans’ phone records, from going forward altogether.

McConnell, his deputies and allies on the Intelligence Committee, made repeated pleas on Monday and Tuesday to support his changes. McConnell framed the amendments as “discreet and sensible improvements” that would ensure the system the House bill calls for “can in fact actually work.” But after repeatedly giving ground in the debate over domestic surveillance, McConnell had too little left to stand on.