Falsifying expense accounts is an old custom. He was caught, and is returning the money. Whether or not there was criminal intent is up to the Mounties. He is a senator, thus has little to do with making policy.

The parties on the outside looking in consider it a YUMMY subject (dunno what that YMMV is), and are riding it in hopes of garnering votes, but it has nothing to do with the important issues of the day.