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Both sides prepare for runoffs in key Senate races

Sen. Mary Landrieu, D-La., speaks during a press conference on Capitol Hill April 1, 2014 in Washington, DC. Landrieu is one of nine Democrats targeted in an ad buy by a Koch-backed conservative group.

Allison Shelley, Getty Images

Democrats and Republicans are vying for control of the Senate in next month's midterm elections, but they may not know which party prevails until December or January.

Two key Senate races, in Georgia and Louisiana, could come down to runoff elections should no candidate garner more than 50 percent of the vote on Election Day on Nov. 4.

Anticipating that scenario, partisan groups trying to influence the races are already reserving airtime for ads in those states in the months to come, the Wall Street Journal reports. The National Republican Senatorial Committee (NRSC), for instance, has purchased $3.4 million worth of airtime in Louisiana ahead of the state's potential December runoff. The NRA, meanwhile, has already reserved more than $1 million to support Republican Rep. Bill Cassidy in Louisiana after Nov. 4. Other groups preparing for runoffs include the conservative group Freedom Partners, the conservative group FreedomWorks, the pro-Democratic Senate Majority PAC, and the Service Employees International Union.

In Louisiana, should no candidate win at least half the vote, there would be a runoff on December 6. Rather than holding primary elections, the state puts every candidate on the ballot on Election Day. A recent CNN/ Opinion Research Corporation poll suggests a runoff is likely. Democratic Sen. Mary Landrieu wins 40 percent support among likely voters, Cassidy wins 43 percent, while tea party Republican Rep. Rob Maness wins 9 percent. Should the race go to a runoff, it would still be close -- the poll shows Cassidy taking 50 percent in that scenario while Landrieu would win 47 percent.

In Georgia, where candidates are competing to replace retiring Republican Sen. Saxby Chambliss, a potential runoff election would take place on January 6 -- one day after the new Congress is set to convene. A poll released last month by the Atlanta Journal Constitution shows Republican David Perdue garnering 45 percent, while Democrat Michelle Nunn wins 41 percent and Libertarian Amanda Swafford takes 6 percent.