>By making DC a state, they nullify the constitution by removing the only area in the country they (the government) is authorized to control all of the United States.
US Constitution Article 1, Section 8.
(Congress' duties include: )
"To exercise exclusive Legislation in all Cases, whatsoever, over such District (not exceeding ten Miles square) as MAY, by Cession of particular States, and the Acceptance of Congress, become the Seat of the Government of the United States, and to exercise like Authority over all Places purchased by the Consent of the Legislature of the State in which the Same shall be, for the Erection of Forts, Magazines, Arsenals, dock-Yards, and other needful Buildings; … "
Congress has the right to exclusive legislation of the 10 square mile seat of the US government (DC).
This 10 square mile was created by Congress.
IF Congress has the exclusive legislation,
AND IF Congress passes the legislation to create DC as the 51st state,
THEN, it seems it would be in violation of the US Constitution, which would be a case brought by < who? to be litigated in front of the US Supreme Court.
Congress theoretically could create a new 10 mile square area for the seat of government, in a republican state to reduce the number of House Reps, and further solidify their majority.