Saskatchewan's position is that the Senate is beyond reform, and should be abolished. The province is backing the government's position that seven provinces representing 50 per cent of the population can abolish the Senate, rather than a unanimous decision by all the provinces and territories.
Alberta will also support what's known as the "7/50 formula" for Senate abolition, although the province, having elected four senators, prefers an elected Senate.
The federal government is asking the top court for an opinion on whether it can unilaterally impose term limits on senators. It also wants to know whether it can mandate what it calls "consultative elections," meaning the prime minister would not necessarily have to name people who have won elections in their provinces to the Senate.
Although the government's current position is not one of Senate abolition, Prime Minister Stephen Harper has said repeatedly that the Senate must be reformed, and if not, abolished.
This stance is why one of the government's questions before the court is whether only the backing of seven provinces is needed to get rid of the Senate.
On Tuesday, the court heard arguments from government lawyers who pointed out that a constitutional amendment of any kind requiring the agreement of all provinces has never happened.
On the same day, Ontario, Quebec, Nova Scotia, Manitoba and New Brunswick all insisted that unanimity among provinces is necessary for Senate abolition, and that the government cannot unilaterally change senators' tenure or method of selection to sit in the upper chamber.
On Wednesday, Newfoundland and Labrador, P.E.I., British Columbia, Northwest Territories and Nunavut will have their turn to make arguments before the court.