Further to Bob’s post citing Frye on the interchangeability of the Liberals and the Conservatives before the advent of the C.C.F.  From Stephen Leacock‘s “The Great Election in Missinaba County” in Sunshine Sketches of a Little Town.

Let me begin at the beginning. Everybody in Mariposa is either a Liberal or a Conservative or else is both. Some of the people are or have been Liberals or Conservatives all their lives and are called dyed-in-the-wool Grits or old-time Tories and things of that sort. These people get from long training such a swift penetrating insight into national issues that they can decide the most complicated question in four seconds: in fact, just as soon as they grab the city papers out of the morning mail, they know the whole solution of any problem you can put to them. There are other people whose aim it is to be broad-minded and judicious and who vote Liberal or Conservative according to their judgment of the questions of the day. If their judgment of these questions tells them that there is something in it for them in voting Liberal, then they do so. But if not, they refuse to be the slaves of a party or the henchmen of any political leader. So that anybody looking for henches has got to keep away from them.