WASHINGTON -- Senate Democratic leadership seems poised to acquiesce to Sen. Rand Paul's (R-Ky.) demand that the chamber vote on an amendment that would restrict national security officials from examining gun dealer records in their efforts to track potential terrorists.

The Kentucky Republican had been insisting that such language at least receive a vote as an addition to the extension of the USA Patriot Act. As of Wednesday night, it appeared that he would be stymied.

By Thursday morning, however, the landscape had changed and multiple sources on the Hill confirmed to The Huffington Post that a vote on that amendment and one other would happen -- likely as a means of expediting passage of the Patriot Act's extension.

It's unclear whether the Paul amendment, which would restrict law enforcement from accessing firearm receipts, will have the 60 votes needed for passage. [UPDATE: The amendment failed to pass the Senate on Thursday afternoon, garnering only ten votes, 50 short of the amount needed to achieve cloture.]

There are, certainly, objectors in the Senate. When Reid initially tried to get the amendment a vote, by packaging it with five others and asking for a unanimous consent (UC) agreement to bring it to the floor, he was stopped by members of his own party.

Sen. Frank Lautenberg's office confirmed on Thursday that the New Jersey Democrat had put a "hold" on the Paul amendment, thereby killing the UC agreement. An aide to the senator, Caley Gray, told The Huffington Post that "all options remain on the table" for stopping the language from being inserted into the Patriot Act's extension.

Additionally, Lautenberg has introduced an amendment of his own, this one to close the "terror gap" by giving federal authorities the power to block the selling of guns and explosives to individuals on the terrorist watch list. As of Thursday morning there was no word from Democratic leadership if that amendment, like Paul's, would get a vote.

The possible passage of Paul's amendment had left gun-control advocates nervous, spurring a last-minute effort by several groups to draw attention to, and condemnation of, the measure. Those efforts appeared to have reaped benefits when Lautenberg put the hold on the amendment and Senate Majority Leader Harry Reid (D-Nev.) decided to bring the Patriot Act extension to the floor without it.

Why Reid reversed course isn't entirely clear, though the likelihood is that he and others (President Obama chief among them) felt that the benefits of getting the Patriot Act extended before it expires at midnight on Thursday outweighed the risks of tempting Paul to hold up the bill over his amendment. The possibility also exists, as one Senate aide speculated, that Reid knows the 60 votes aren't there for Paul's amendment to pass, and is comfortable letting it come to a vote if it means placating the Kentucky Republican.

UPDATE: Paul's Senate campaign committee put out a statement on Thursday saying that Republican leadership is now responsible for holding up his amendment and may be whipping support against it.

Word is that the GOP leadership is holding up Senator Paul's amendment to protect law-abiding gun owners from the PATRIOT Act. As if that wasn't bad enough, we are also hearing that GOP leadership is lobbying other Republicans to oppose the amendment!