Louisiana Senator Mary Landrieu loses seat in runoff election: CNN
Louisiana Sen. Mary Landrieu speaks with attendees of the 2011 National Guard Family Program National Volunteer Workshop, July 25, 2011. (U.S. Air Force photo/Sgt. John Orrell)

Incumbent Senator Mary Landrieu (D-LA) lost her seat in the U.S. Senate Saturday, falling to Republican Congressman Bill Cassidy in a runoff election, according to CNN.

CNN called the election for Cassidy within a half-hour of the polls closing.

Landrieu, a member of a New Orleans political dynasty, has held the seat since 1996 when she replaced John Bennett Johnston, Jr., also a Democrat.

Landrieu was forced into the runoff after receiving only 42 percent of the vote in the November election, short of the 50.1 percent required for re-election.

In recent weeks Landrieu has frantically campaigned to hold onto her seat, including backing a measure to move forward with the construction of the Keystone XL pipeline, a move popular in her state but at odds with national Democrats.

With the loss, Republicans picked up nine Democratic seats in the Senate in 2014, giving them control of 54 seats when they convene in January, 2015.