Acknowledging the donkey in the room, in the way of explanation, Cassidy told his supporters in the bar that Huey Long, in 1930, was the last U.S. Senate candidate to overthrow an incumbent in Louisiana. Apparently there weren’t any John Overton groupies in the crowd, for no one objected to the factoid.
Long was indeed elected in 1930, but did not claim the seat until 1932, wanting to maintain control over the state rather than hand it over to the lieutenant governor.
After arriving in D.C. in 1932, Huey set his sights on Louisiana’s other Senate seat and put up his ally, then-Congressman John Overton, who took down incumbent Sen. Edwin Broussard. A Senate committee looked into fraud and abuse in relation to the 1932 campaign, noting the “deplorable and distressing political conditions” in Louisiana, but submitted a report with no recommendations.
So it was Overton, not Long, who last overcame an incumbent U.S. senator on a Louisiana ballot.
For whatever it’s worth, if senior Sen. Mary Landrieu is looking to make a similar splash, there’s another bar in Baton Rouge that might be available for a last minute campaign event — Uncle Earl’s on Perkins Road.