The Seventeenth Amendment in its entire text states as follows:

“The Senate of the United States shall be composed of two Senators from each State, elected by the people thereof, for six years; and each Senator shall have one vote. The electors in each State shall have the qualifications requisite for electors of the most numerous branch of the State legislatures.

When vacancies happen in the representation of any State in the Senate, the executive authority of such State shall issue writs of election to fill such vacancies: Provided, That the legislature of any State may empower the executive thereof to make temporary appointments until the people fill the vacancies by election as the legislature may direct.

This amendment shall not be so construed as to affect the election or term of any Senator chosen before it becomes valid as part of the Constitution.”

Put in simple terms, the Seventeenth Amendment provides that:

1. the United States Senate shall composed of two Senators from each State;
2. the Senator from a particular state shall be elected by the people of that particular state;
3. the term of office for a Senator is six years;
4. each Senator shall have one vote in the Senate;
5. the electors for the Senator election shall have the same qualifications required for the electors of the State legislature election;
6. when the seat of a Senator for a particular state becomes vacant, the executive authority of that state shall conduct elections to fill the vacancy; and
7. the legislature of the particular state may empower the executive authority of the state to appoint a temporary Senator until a new Senator is elected.

The Seventeenth Amendment, ratified in 1913, provides for the direct election of U.S. senators from various states by the citizens of the respective state itself.  Until 1913, it was the state legislatures of the respective states that elected the senators from each state.  Thereafter, the Seventeenth Amendment superseded Article I, Section 3, Clauses 1 and 2 of the Constitution and transferred Senatorial Elections from the state’s legislature to popular election by the people of the state. 

The Seventeenth Amendment also provided a contingency provision which enables a state’s governor, if authorized by the state legislature, to appoint a Senator in the event of a Senate vacancy until either a special or regular election to elect a new Senator was held.