I suppose political scientists and historians (and those there) would be better than I at analyzing if the "Old Tories" were consistently in charge of the party from Macdonald to Mulroney.  As the actual book is about Stanfield to Harper, it seems to fit better there.  And Mr.Martin does have a point about the "ceiling" - although, on the other hand, the Conservatives weren't all that successful as the "Old Tories" for many years (as acknowledged in the column).

At any rate , given the permutations through policy from Macdonald to Borden to Bennett to Diefenbaker to Mulroney to Harper, I think it's overstated.  It's worth remembering that Diefenbaker wasn't considered truly Conservative by many at his time.

Also worth remembering, for context, the Liberals under Louis St. Laurent saw fit to ban "crime comics" in response to popular demand.  How's that for reactionary?  That electoral  incarnation of the Liberals was more successful than its successors.