Sen. Rand Paul (R-Ky.) sent a letter to Senate leaders today warning that he is prepared to force a vote on ending aid to Pakistan if he cannot reach an agreement with them to hold the vote in a timely manner.

Paul’s bill would end all foreign aid to Pakistan unless the country releases Dr. Shakil Afridi, who reportedly aided the U.S. in finding al-Qaida leader Osama bin Laden, from prison. Afridi has been convicted of treason for his alleged role helping the U.S. government stage a fake vaccination campaign that allowed for the collection of DNA from the people inside bin Laden’s compound in Abbottabad, Pakistan. He faces 33 years in prison, and his appeal is set for July 19, according to Paul.

In his letter to Majority Leader Harry Reid (D-Nev.) and Minority Leader Mitch McConnell (R-Ky.), Paul threatens to use a procedural maneuver that, by custom, is reserved for the Majority Leader. Any Senator can collect 17 signatures from colleagues to force a vote on a motion to invoke cloture, or limit debate, on a bill or motion, but the procedure has traditionally been the province of the Majority Leader, and on occasion, the Minority Leader.

“I have worked consistently to bring awareness to Dr. Afridi’s plight, and I have offered legislation to deny any current or future foreign assistance to the Pakistani government until they reverse course and free Dr. Afridi,” Paul wrote. “In pursuing a resolution to this situation, I have gained the necessary number of signatures on a cloture petition to force a vote on my legislation on the Senate floor. If Dr. Afridi is not released upon appeal, I will seek such a floor vote at the earliest opportunity. This legislation would deny Pakistan tens of billions of dollars in foreign assistance into the future if Dr. Afridi is not freed — extending through the duration of his 33-year prison sentence, if necessary.”

But Paul left open the possibility of working out an agreement with both leaders to hold a vote on a date certain if Afridi remains in prison.

Paul contends that “Dr. Afridi’s small but important contribution to the successful killing of the world’s most infamous terrorist has been greeted with condemnation by Pakistani tribunals. His home was seized, his family was forcibly relocated and he has likely been subjected to the harshest of interrogation tactics during his detention.”