A possible solution

Following up on Malcolm's clear evidence of the futility of any formal pre-election coalition, I now wonder whether my conclusion that broader public opinion shifts can have a far greater influence than attempts to divvy up seats might point toward another form of cooperation. So let's take a step back and revisit what was little more than a throw-in when I first put together a rough draft of a more complete basis for NDP/Lib cooperation.

Assuming for the moment that any more formal deal isn't likely to come about prior to the next election, what would supporters of the NDP, Libs and Greens think of an informal agreement that their national campaigns would avoid messages which tend to lead to disputes between them rather than a focus on the Cons?

After all, it's been fairly well documented that the Libs' strategy for several election cycles has depended on poaching soft NDP votes at the tail end of each campaign by saying the NDP can't form government - and that much of the NDP's time has consequently been spent inoculating itself against that result by offering reasons not to vote for the Libs. (Similar dynamics have mostly existed between the Libs/Greens and NDP/Greens as well, with some exception for the Dion/May pact in 2008.) And in every case, the result has been to reinforce Con messages about each opposition party while allowing Harper to escape criticism he'd otherwise face for his record.

But what would happen if the NDP, Libs and Greens agreed not to use their national campaign to spread the messages which lead to that tug-of-war, and to similarly encourage local candidates to focus criticism on the Cons rather than each other? Wouldn't the end result almost certainly be a campaign focused on more positive ground for all of the opposition parties, with the Cons having to fight far harder just to retain their current turf?

Of course, there would still be some need for the opposition parties to differentiate themselves from each other - and such an agreement might be prohibitively difficult to police. But I have to wonder whether it might provide a far more feasible yet no less effective means of escaping the current stalemate than any pact involving parties running less than a full slate of candidates.