If this resolution passes, the result is simple to predict. This resolution will mean less votes for the Conservative Party. More specifically, it will mean less votes for the Conservative Party is close races they need to win.
In both of his posts Andrew suggests that P-90 leaves the CPC vulnerable to being smeared by the Liberals and the media as having a "hidden agenda". Nevermind that. If the CPCs adopt P-90, they actually create legitimate reason for doubt in the minds of swing voters.
Supporters of frequent free votes suggest that they leave Members of Parliament to represent their constituents' views. But this doesn't offer much solace to the swing voter. Consider a fiscally-conservative, socially-moderate voter living in Belinda Stronach's riding. If this voter is pro-choice and pro-SSM, the fact that Stronach is also pro-choice and pro-SSM brings no comfort if the Conservatives have adopted P-90. If these issues are important to the swing voter, a CPC vote is a gamble, because it can help to create a Conservative majority with unpredictable results. Who wants their vote to lead to unpredictable results and unknown policies?
P-90 would seem to be a losing strategy for the Cons. However, it is also an easy way out for a party that is struggling a bit to manage its diversity of views. The smart thing for the Conservatives to do would be to hammer out their differences and come up with an actual platform -- or, as Andrew puts it, "balanced compromise-laden positions on issues of conscience". But hammering out differences is not easy. Anyway, I'm wishing them luck since I think Canada is better with 3 functioning national parties.