Legal Question in Constitutional Law in California

Because Article 1, section 8 makes no such limitation on the power and authority of Congress? Read the whole section. It's a list of about 50 enumerated powers beginning with, "The Congress shall have Power To lay and collect Taxes, Duties, Imposts and Excises, to pay the Debts and provide for the common Defence and general Welfare of the United States; . . ." and goes on from there with 17 more clauses of listed powers. In fact the very clause that you are basing your misinterpretation on ends with the words, "dock-Yards and other needful Buildings; AND" (emphisis on AND added). It is then followed by: "To make all Laws which shall be necessary and proper for carrying into Execution the foregoing Powers, and all other Powers vested by this Constitution in the Government of the United States, or in any Department or Officer thereof." But other than that I can't think of any reason Congress thinks it has authority outside Washington DC, military bases and ports.

The clause you describe only says how big the capital (which had not been named or built yet) would be. It does not say Congress only has authority inside the capital. Limiting the authority of the national government that way would have been absurd.