RATIFICATION TIME LIMIT
There is no time limit provision anywhere in the U.S. Constitution. The first time a time limit was permitted was through the Supreme Court in 1917 for the 18th Amendment on the grounds that "ratification must be within some reasonable time after the proposal.”
The 19th Amendment for women's suffrage did not have a time limit and took 72 years to win. Yet Congress chose to limit the states to ten years to approve the Equal Rights Amendment for women. Not surprising, Congress's deadline expired before the final three states could approve.
The chart below displays the inconsistent use and placement of time limits on the 27 Amendments to the Constitution. When the time limit is placed within the actual text of the amendment, such as DC Voting Rights, it is absolute. However, in the case of the Equal Rights Amendment, the time limit was placed in the resolving clause (so as not to clutter the Constitution with redundant language). Therefore, it is possible for a subsequent Congress to extend or repeal the time limit without changing the original intent of the amendment.
Courts have long held that although the government is bound by the Constitution, one Congress cannot "bind" future Congresses. In other words, any Congress can reverse the decisions of a previous Congress.