As statehood for Washington, D.C. was argued in the House Oversight and Reform Committee last week, Senator Charles Grassley believes it is unlikely to pass in the Senate if they still have the filibuster rule.

Though Democrats have a slim majority hold of the Senate, they would need 60 votes to pass legislation to make Washington, D.C. the nation’s 51st state. Grassley poses an argument on the proposal, “But I would also raise the question whether or not it can be done by simple legislation because the Constitution lays out the District of Columbia is a federal district and it was separated from the states because we didn’t want states to have jurisdiction over the federal government and so how could D.C. become a state without amending the Constitution.”

House Resolution 51 proposes to shrink the national capital to a small complex of federal buildings, while allowing the rest of the district to become a state. The Constitution states that the Capitol not exceed 10 miles square. As legislation is expected to face the filibuster hurdle in the Senate, a number of senators have pushed for various filibuster reform proposals to allow legislation to pass by a simple majority of 51 votes.