I think the move by the NDP to take the high ground on the senate and push for the abolition of this patently unrepresentative body is a great way to make the NDP the populist party in Canada. One reason the Reform party did so well in the early 1990s was because of a strong desire for a Triple E Senate, the Reform party took a lot of western support from the NDP by making senate reform
The Senate is a great way for the NDP to show a strong fundamental difference between them and the Liberals and the Conservatives. After more than seven years in government the Conservatives have lost all their moral authority on senate reform and given how some of the senators have acted that were appointed by Harper, Conservative senators are at best a political embarrassment.
The cost of the senate is not a huge cost for the federal government, but the number is more than large enough that the numbers sound wildly wasteful to most people. Senators are also paid much more than vast majority of Canadians but do virtually nothing that the public can see as relevant let alone look like they have to work hard at all. Your average senator has a work load that is less than the working poor in this country that have to hold several jobs. Paying rich people high wages for an irrelevant job that is very easy is an easy political campaign. Defending keeping 105 politicos that do nothing useful is political suicide.
If the Liberals really come out defending the status quo senate, they will be seen as elitists that are out of touch with the people in the country. The Liberals will end having to be defending the actions of people like Duffey and Wallin. As a wedge issue with the Liberals, it is a brilliant one.
As an issue for the NDP in the west it is also a very important one. The NDP was for decades mainly a western populist party but this was destroyed with the rise of the Reform party. Western Canada currently provides the Conservatives with a solid block of seats, a big enough one to make it very hard for any other party to win government. For the NDP to become government they need to break the Conservative hold on the west. Abolition of the senate could be the way for the NDP to break an extra 10 to 20 seats from the Conservatives in the west.
People are saying "but it takes a constitutional amendment to get rid of the senate" - so what. Getting seven provinces representing more than 50% of the population to abolish the senate is one of the few amendments I can see easily passing because of the overall general loathing of the senate in the country and the strong public opinion in favour of abolition.
Very few people in Canada like the status quo and a strong majority favour abolition. Not being in favour of abolition will mean being painted as being in favour of the status quo. It will be hard for almost any premier to actively defend keeping the status quo in the senate because of the political ammunition it gives to their opposition. A premier that defends the senate does so knowing that the very existence of the body goes utterly counter to Canadian values of democracy and fairness. Given public opinion about the senate, I can not see how campaigning for the status quo senate will attract the four premiers needed to stop the abolition.
Because they are different in their approach to politics, let us say that Quebec was willing to defend the status quo, there would still have to be three more provinces supporting them or provinces with 8,835,343 people. Unless Ontario backs Quebec it means at least three other provinces would have to back Quebec to keep the senate.
There is no chance any of the four western provinces will support keeping the senate. As long as the NDP is in power in Nova Scotia they are not going to support keeping the senate. Ontario is a big question mark, though if after the next election the NDP holds a serious balance of power I expect Ontario to support abolition of the senate. I also think that in general the mood in Ontario is no longer as accepting of unfair situations "for the benefit of confederation".
This leaves PEI, New Brunswick and Newfoundland and Labrador as possible provinces that could support keeping the senate.
In the case of PEI defending the status quo means defending Mike Duffey. Even though he was a Conservative, of Ghizz were to defend keeping the senate it opens up a campaign by the PCs to win the next provincial election.
In Newfoundland and Labrador the PC government is facing a rising popularity of the NDP. In Newfoundland and Labrador one of their senators is Fabian Manning, a senator that resigned in 2011 to run for the Conservatives and when lost again he was reappointed to the senate. Hardly a poster boy for the senate when twice the people in Newfoundland and Labrador voted against having him as an MP. I think Kathy Dunderdale does not have the political capital to defend the senate.
The assumption of Quebec being willing to support the status quo is also not necessarily true. In a minority parliament the opposition parties can pass a resolution supporting the abolition of the senate without the consent of the PQ government. It is a resolution of the provincial house that is needed to change the constitution, not support of the provincial government.
Of course if the NDP were to become government and want to abolish the senate, it would have to get the agreement of the senate to do so. That may not be that easy, though I suspect a majority of the current senate could be shamed into agreeing to abolition. In their hearts they know the institution is fundamentally wrong and at odds with modern Canada. If they refuse, it gives the NDP some great political capital, if they agree the NDP can claim to be the party that brought Canada's parliament into the modern age, either way the NDP wins.