Prominent senators have put Gary Gensler’s nomination to head the Commodity Futures Trading Commission (CFTC) on “hold” in a bid to force the administration to take a tougher line on commodity regulation.

Gensler’s nomination was approved by the Senate Agriculture Committee on March 16, but almost immediately put on ice before it could reach a vote on the Senate floor by Senator Bernie Sanders (Independent, Vermont) and one other unidentified senator.

Holding a nomination is a relatively common procedure allowing any senator to request a delay before it moves to a vote on the Senate floor, ostensibly to seek more information or testimony from the nominee.

However, the practice is controversial because it allows even a single senator to delay the confirmation process, in some cases indefinitely, and because holds can be placed anonymously. Senators simply notify their party’s floor leader, who will prevent the nomination from coming up on the Senate calendar for a vote.

While the practice is arcane, it plays a crucial role in the nomination process. Holds can block nominees with whom the senator has a strong personal or political disagreement; punish past transgressions by the nominee; or create bargaining leverage with the administration on related issues, or even unrelated ones.