Senate Majority Leader Harry Reid (D-Nev.) on Tuesday blocked Sen. Rand Paul (R-Ky.) from attaching an amendment to the farm bill that would withhold U.S. aid to Pakistan.

Reid asked for unanimous consent Tuesday to consider a batch of five amendments to the farm bill, the Agriculture Reform, Food and Jobs Act of 2012 (S.3240), but Paul objected, arguing that his amendment on withholding aid to Pakistan should also be included.

In response, Reid performed a procedural move called “filling the tree,” or taking up all the amendment space, to keep Paul’s amendment from being considered.

The amendment would have defunded U.S. aid to Pakistan until the country frees an imprisoned doctor who helped the CIA find Osama bin Laden.