Article One of the United States Constitution gives the Senate the power to "determine the elections, returns, and qualifications" of its own members.
As a result, the Senate has been asked to review the election of one of its members many times.
Governor Rod Blagojevich (D-IL) chose Roland Burris (D-IL) as the Senator-designate from Illinois to fill the seat left vacant by then President-elect Barack Obama (D-IL).
Senate majority leader Harry Reid (D-NV) refused to seat Burris due to allegations that Governor Blagojevich had tried to sell the senate seat left vacant by Obama.
The Secretary of the Senate and the Senate Parliamentarian deemed Burris's credentials valid, and Senate leaders seated Burris.