For the purpose of selecting senators and representatives in the state legislature, the states are generally divided, under the provisions of their constitutions, into senatorial and representative districts, and from each one or more members are selected for the respective branches of the legislative body.

By the constitution of the United States it is provided that two senators shall be chosen in each state by the legislature thereof (Art. I, § 3, ¶ 1), the term of office being six years. There is now some popular agitation in favor of the choice of senators by popular vote instead of by legislative selection, but any such change would require a constitutional amendment. In case a vacancy occurs by resignation or otherwise, while the legislature of the state is in session, it is filled by the legislature, but if a vacancy occurs during the recess of the state legislature, the executive thereof may make a temporary appointment until the next meeting of the legislature (Art. I, § 3, ¶ 2).

The members of the House of Representatives of the United States are chosen every second year by the people of the several states by the electors of the state having the qualifications requisite for members of the most numerous branch of the state legislature (Art. I, § 2, ¶ 1). The number of members from each state is determined by the enumeration in the census taken each ten years of the whole number of persons in each state, excluding Indians not taxed (Art. I, § 2, ¶ 3, and Amend. XIV, § 2). Congress determines after each census the number of members of which the House of Representatives shall be composed, and apportions them among the various states in proportion to population, each state being entitled, however, to at least one representative. The provision of the Fourteenth Amendment that representation of any state in Congress may be reduced proportionally if the right to vote is denied to any of the male inhabitants of such state, being twenty-one years of age and citizens of the United States, has not as yet been the subject of any final action on the part of Congress.

By federal statute (1901, following that of 1872) the Representatives apportioned to each state are to be elected by districts composed of contiguous and compact territory, and containing as nearly as practicable an equal number of inhabitants, not more than one Representative to be elected from any district. But even under this plan it may at times be necessary (and the Act so provides) to elect members at large for the whole state as for instance where the representation of the state has been changed as the result of a reapportionment, and the legislature has not redistricted the state accordingly.

A representative in Congress must have attained the age of twenty-five years and have been for seven years a citizen of the United States, and at the time of election an inhabitant of the state in which he is chosen (Art. I, § 2, ¶ 2). Vacancies are filled by a special election called by the state executive (Art. I, § 2, ¶ 4).

A Senator must have attained the age of thirty years, and have been for nine years a citizen of the United States, and at the time of his election an inhabitant of the state for which he is chosen (Art. I, § 3, ¶ 3). Vacancies are filled by the legislature of the state; but in case of a vacancy during a recess of the legislature the state executive may make a temporary appointment (Art. I, § 3, ¶ 2).

The times, places, and manner of holding elections for senators and representatives in Congress are prescribed in each state by the legislatures thereof, unless Congress makes provision on the subject, which it may do, except as to the places of choosing senators (Art. I, § 4, ¶ 1). By federal statutes the times and manner of electing senators and representatives are now specifically regulated (Acts of 1866, 1871, 1872, 1901). Senators are to be chosen by the legislature chosen next preceding the expiration of the term of a senator, and on the second Tuesday after its organization by a majority vote of each house voting separately; but if the houses do not agree then by a majority vote of the members of both houses in joint session. Vacancies are to be filled by the legislature in the same manner. The result of the election is certified by the executive, countersigned by the secretary of state. Representatives are to be chosen by districts on the Tuesday after the first Monday of November of each second year for the Congress which commences the next year. Vacancies are to be filled as prescribed by the laws of the respective states. The control of elections is left with the states. (See below, § 200.)

By statute (1817) provision has been made for the election by each territory of a delegate to Congress, who has all the privileges of a member except the right to vote.

It would not be profitable to go into further detail as to the provisions of state and federal constitutions and statutes relating to representation in legislative bodies. It is sufficient to say in general that these questions seldom come before the courts, for the reason that by provision of most of the state constitutions, as well as under the federal constitution (Art. I, § 5, ¶ 1) each house of a state legislature or of Congress is the judge of the elections, returns, and qualifications of its own members. Contests as to the validity of elections are therefore determined by the house in which membership is claimed, and the action of that house is final and conclusive. Each house has also the power to expel a member for such cause as it may deem sufficient.

By provision of the federal constitution (Art. I, § 6, ¶ 1) senators and representatives are privileged from arrest in all cases except for treason, felony, or breach of the peace during attendance at the sessions of their respective houses and in going to and returning from the same; and they are also exempt from being questioned for any speech or debate in either house, save under the authority of the house itself; and similar privileges are granted in state constitutions. The object of the privilege from arrest is to exempt members from being interfered with by judicial procedure while in the discharge of their duties. At other times and in other respects they are subject to the jurisdiction of the courts as fully as private persons. Indeed, the exemption is of little practical value, as arrest or seizure of the person is no longer generally authorized except for crime, and all crimes of a serious nature are included within the description of treason, felony, and breach of the peace. (Williamson v. United States.)