What if: Control of the Senate depends upon Louisiana run-off?

[Vosem]

If Senate control will depend entirely upon Louisiana, then the race will be completely nationalized and Landrieu will lose. Period -- not only has Louisiana has moved right since 2002, but party allegiances have also solidified significantly since then. Obama's disapproval in Louisiana is built on much more solid ground than Bush's approval. If Senate control doesn't depend on the runoff (like it didn't depend in 2002), then Landrieu is certainly a canny politician and may be able to get a victory. But the scenario you described above is not one where she can keep office.

[Vosem]

Wait, so what would be the situation in the Senate? I mean, the runoff would take place before the 114th Congress begins, but if it didn't, who would control the Senate, Republicans?

Dems through Biden. The runoff is in early December, so a moot point if Cassidy wins, as he probably would in that scenario.

No. If Democrats need Landrieu to maintain control of the Senate, then the Senate is split 50-49 to the Republicans without her (she is the 50th vote, and then Biden is the 51st). If this turns into a Minnesota 2008 type scenario, then as I understand it is the Republicans who will control the Senate in the interim -- assuming a majority of non-vacant Senate seats (50/99) is necessary. If it is a majority of all seats (51/100) necessary and the Senate is split 50-49 R in 2015...then I guess it goes to SCOTUS? No idea.