If this doesn't encourage Canadians to vote Conservative, nothing will. However, it is hard to see Ontario adjusting to a Conservative government.
This proposal won't pass because when they are sober enough to think about it, it means polygamists from the fundamentalist Mormon sects (such as the Fundamentalist Church of Jesus Christ of Latter Day Saints) must likewise be legalized. When you allow them legal status we will see these groups move to Canada en masse.
And everyone know Mormons are most politically conservative of almost every group in the US (the more mainstream Mormon church has its members mainly in Utah. In the 2004 US presidential election, Bush got more than 70% of votes in Utah as a whole). If each and every one of the 37,000 move north to Canada and each "family" has 25+ children, it will mean BC instantaneously goes Conservative and it won't take more than 40 years for even Toronto to turn Red had they decided to resettle in GTA. This will probably send shivers down every Canadian "moderates"/msinstreamers/leftists' spine.