I'm sure it has been used that way! I'm thinking more about the areas of agreement that exist among people with different politics. Maybe we don't agree on the exact right destination for e.g. some $2T chunk of money, but we agree that it shouldn't be used to kill random people overseas. That ain't centrist! I occasionally lurk over at Caitlin Johnstone's site and I get a kick out of the "cross-ideological collaboration" she's doing.