BATON ROUGE, La. (AP) — Republican Rep. Bill Cassidy is favored to defeat Democratic Sen. Mary Landrieu  in a Louisiana runoff.

But the campaign leading up to Saturday's expected outcome hasn't exactly revealed what kind of senator Cassidy would be.

The Baton Rouge physician has campaigned as a staunch critic of President Barack Obama and tied Landrieu to his administration, which is unpopular in Louisiana.

But just 12 years ago, Cassidy supported Landrieu's first re-election. About the same time, he was sharply critical of Republican Bobby Jindal, who now serves as Louisiana governor. Cassidy said during Jindal's first campaign that he was a disaster for health care in Louisiana.

GOP establishment leaders say they have no worries about Cassidy. With him, the party would have 54 seats when the Senate convenes in January.