Senate Minority Leader Mitch McConnell (R-KY) wanted to prove on Thursday that Democrats don’t have the votes to weaken Congress’ authority on the debt limit. Instead they called his bluff, and he ended up filibustering his own bill.

The legislation, modeled on a proposal McConnell offered last year as a “last-choice option” to avert a U.S. debt default, would permit the president to unilaterally lift the debt ceiling unless Congress mustered a two-thirds majority to stop him. President Obama has championed the idea.McConnell brought up the legislation Thursday morning. Senate Majority Leader Harry Reid (D-NV) initially objected, seemingly proving the Republican leader’s point that it cannot pass the Senate. But then Reid ran it by his members and, in the afternoon, agreed to hold that same vote. This time it was McConnell who objected.

“The Republican leader objects to his own idea,” Reid declared on the floor. “So I guess we have a filibuster of his own bill.”

McConnell claimed he never agreed to hold a simple majority vote on the bill.

“What we’re talking about here is a perpetual debt ceiling grant in effect to the president. Matters of this level of controversy always require 60 votes,” the GOP leader said.

Senate Majority Whip Dick Durbin (D-IL) scoffed at the notion that a senator would ask for a vote on a bill in good faith while requiring that it be “filibuster-proof.”

“This may be a moment in Senate history when a senator … filibustered his own proposal,” he said. “I don’t think this has ever happened before.”

To McConnell, raising the debt limit must require deep spending cuts.

“If the Democrats want to pass the debt ceiling, as we did last year, with two trillion dollars in spending cuts, we’d be more than happy to have that conversation,” a Senate Republican leadership aide told TPM. “But there is bipartisan opposition to giving this or any President the unlimited authority to raise the debt ceiling.”

That was the point McConnell set out to make this morning, but Reid’s maneuvering left the Republican in an awkward position. And the Democratic leader vows more votes.

“Senator McConnell’s filibuster prevented us from having this vote today,” he said in a statement, “but I will continue to seek an agreement to hold an up-or-down vote on his proposal to avoid another debt ceiling debacle.”