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.