It is superfluous to try by the standards of theory, a part of the constitution which is allowed on all hands to be the result not of theory, but "of a spirit of amity, and that mutual deference and concession which the peculiarity of our political situation rendered indispensable" . . . the equal vote allowed to each state, is at once a constitutional recognition of the portion of sovereignty remaining in the individual states, and an instrument for preserving that residuary sovereignty.