While I agree with the theory of illegal incorporation of DC in 1871, the problem is that all Amendments to the Constitution if ratified by the required number of states, must be considered part of the Constitution. Even if we are to argue that the Congresses since 1871 are of questionable legality, the states still ratified the Amendments nonetheless, and nobody is questioning the legality of the state governments. Where a lot of this 1871 incorporation theory gets lost, is that only DC was incorporated. The Congress had technically always been legal, at least in the sense that they states have constitutionally (barring fraud) elected and appointed representatives to go to the Capital. The problem is that DC is technically no longer sovereign territory of the United States Republic. So essentially, the Congress has been legally operating, but unfortunately on foreign territory, where they've been held hostage.