Just when you think it might be worth your time to read John Barber again ...
His article seems to be based on the premise (which he seems to think is undisputed) that all of those NDP voters would vote Liberal, if only there were no NDP. He offers no evidence at all to back that. And even if it were true, the fact is that there are pretty significant differences between the NDP and the Liberals, especially the Liberals of Chretien and Martin in recent years. They were pretty much right-of-centre on many issues, as Layton himself loudly proclaimed. To those who want a left-of-centre alternative, Barber appears to be saying, too bad, you don't deserve it, you should sacrifice your desires to some kind of "greater good", that is, defeating Conservatives. That sounds just a bit arrogant.
I've never been an NDP supporter, but I'm glad they are around, and have a credible voice on the national scene based on the fact that they represent a pretty significant minority of people.
Consider people going to the polls in ridings like Parry Sound - Muskoka, which Barber refers to. In rural areas they possibly drive many miles, and at the poll they vote NDP, knowing very well that their candidate won't win. These voters deserve to be treated respectfully and not have their choice denigrated by the likes of Barber.
If he wants the Liberals to win, let them do it the old-fashioned way, by getting a clear plurality of the votes.