The top court begins hearing arguments Tuesday in a historic case that will determine how — or if — the much-maligned, scandal-plagued Senate can be reformed or abolished. Prime Minister Stephen Harper's government has asked the Supreme Court to advise whether it can proceed unilaterally to impose term limits on senators and create a process for electing them.

It has also asked the court to determine whether outright abolition of the upper chamber could be accomplished with the approval of just seven provinces, representing 50 per cent of the population. 

The vast majority of provinces argue that the constitutional hurdles should be set much higher: the approval of at least seven provinces to reform the Senate and unanimity to abolish it.

The provinces acknowledge in factums filed with the court that the higher standard would make reform or abolition more difficult, if not impossible, to achieve — no matter how appealing in the midst of the current Senate expenses scandal.

But they maintain the Senate is an essential part of the bargain struck at Confederation, meant to give a equal voice to small provinces and minorities in counter-weight to the dominance of populous provinces in the elected House of Commons.