On the heels of yesterday’s Magellan Strategies poll which had incumbent Republican David Vitter holding an 18-point lead over Democrat challenger Charlie Melancon comes another poll with Vitter comfortably ahead.

This latest, taken by the Washington, DC firm of Bennett, Petts & Normington on behalf of the Democrat Senatorial Campaign Committee, has Vitter ahead of Melancon by a 48-38 margin in a two-way race. With minor candidates included, though, Vitter leads Melancon 44-35.

The pollster involved, it might be mentioned, had Don Cazayoux leading Bill Cassidy by 17 points (46-29) in mid-October of 2008. Cassidy ended up winning that 6th District congressional race over Cazayoux by a 48-40 margin on Election Day some three weeks later.

Regardless of the accuracy of Bennett, Petts & Normington’s work, one thing seems very clear – Melancon simply can’t poll above the mid-30’s in post-primary polls. Rasmussen’s Aug. 30 poll had him down to Vitter 54-33, the Magellan Strategies poll had him down 52-34 and the DSCC poll has him down 44-35.

In other words, while Vitter’s support hovers within a five-point range of 50 percent, Melancon seems capped around 35.

He can’t win. Chances are he won’t even crack 40 percent.