The division of the States into congressional districts for the purpose of selecting representatives is left to the state legislatures. Congress has, however, provided that these districts shall be composed of contiguous territory. It has become an established rule of political practice, though not one of constitutional obligation, that a representative shall be a resident of the district in which he is elected. Representatives are, however, occasionally elected by districts in which they do not reside, and in such cases there is no question as to their right to sit In certain cases, congressmen at large, that is, from the whole State, are elected. This happens when a State has not been divided into districts, or where, after a reapportionment, an additional representative or representatives have been allotted a State and that State has not redistricted itself so as to provide the necessary additional districts. In such cases, of course, only the additional representatives are elected at large.

6 "Construing the Constitution to authorize a process by which the whole number of representatives should be ascertained on the whole population of the United States, and afterwards 'apportioned among the several States according to their respective numbers,' the Senate [in an amendment which the House accepted] applied the number thirty thousand as a divisor to the total population, and taking the quotient which was one hundred and twenty, ..s the number of representatives given by the ratio which had been adopted in the House where the bill originated, they apportioned that number among the several States by that ratio, until as many representatives as it would give were allotted to each. The residuary numbers were then distributed among the States having the highest fractions." Marshall, Life of Washington, V, 319. Cf. Foster, Commentaries on the Constitution, I, 395.