So it should come as no great surprise that Mr Cameron, in his call for a Tory-Lib alliance to topple Gordon Brown, is now trying to purloin the label "progressive," which has, in British politics at least, traditionally belonged to the centre-left.
I seem to recall there was some discussion about using the word "progressive" in the title of the Liberal Conspiracy blog, but the common consensus was that it's a word that's more readily abused even than "liberal." If so, Mr Cameron's initiative seems to show we probably made the right decision.
Dictionary definitions are no great help. Among those listed by the Free Dictionary are:
Moving forward; advancing. Proceeding in steps; continuing steadily by increments: progressive change. Promoting or favoring progress toward better conditions or new policies, ideas, or methods: a progressive politician; progressive business leadership.
By this token, "progressive" is about as meaningful as that irritating and vacuous piece of management consultancy jargon that is now heard in offices up and down the land - "going forward."
The dictionary also lists a specific definition for "progressive" in the context of taxation, namely:
A tax that takes a larger percentage from the income of high-income people than it does from low-income people.
This is more helpful in terms of defining a centre-left agenda, but then again David Cameron probably claims he believes in this as well, in the sense that we already have a progressive taxation system, and he isn't seeking to make it any less progressive.
Is progressive a word worth fighting over - or should its definition forthwith be restricted to a form of rock music involving long guitar solos, mellotrons and metaphysical imagery?