In Coleman v. Miller 307 U.S. 433 (1939), the US Supreme Court clarified that if Congress, when proposing for ratification an amendment to the US Constitution pursuant to Article V thereof, chooses not to specify a deadline within which the State legislatures (or conventions held in the States) must act upon the proposed amendment, then the amendment remains pending business before the State legislatures (or conventions).

It is none other than the Congress, if and when the Congress should later find itself presented with valid ratifications from the required number of States, which has the discretion to arbitrate the question of whether too much time has elapsed between Congress’ initial proposal of the amendment and the most recent State ratification thereof assuming that, as a consequence of that most recent action, the legislatures of (or conventions conducted within) at least three-fourths of the States have approved the amendment at one time or another.