Amendment XIV, Section 2:
But when the right to vote at any election for the choice of electors for President and Vice-President of the United States, Representatives in Congress, the Executive and Judicial officers of a State, or the members of the Legislature thereof, is denied to any of the male inhabitants of such State, being twenty-one years of age, and citizens of the United States, or in any way abridged, except for participation in rebellion, or other crime, the basis of representation therein shall be reduced in the proportion which the number of such male citizens shall bear to the whole number of male citizens twenty-one years of age in such State.
That is very interesting...
I forgot about that clause of the 14th. At least the Radical Republicans are still fighting for us! Any honest court would declare this an unconstitutional run around the specified amendment procedure. Any dishonest court still able to stop short of treason, would have to at least rule such a Compact required formal consent of Congress (Article I, Sect. 10).