Since there is so much interest in the media of late over the designated successor to Governer General Adrienne Clarkson, it seems to me a good excuse to go review the authority of the Governer General in Canada.
On paper (e.g. in the Constitution), it would appear that the Governer General has quite a bit of power. As the Queen's representative in Canada, she is the head of our armed forces, has the power to dissolve parliament, and even - in theory - appoint ministers and the Prime Minister.
This page from Wikipedia.org does a very nice job of outlining the practical reality of those powers. By a combination of convention and history, they are rather dramatically curtailed. In fact, the wording of the Constitution Act very clearly bounds the powers of our government's "executive" branch in terms of various Acts of Parliament.
What it boils down to is that although the Governer General is the Queen's Representative in Canada, the blunt reality is that the Governer General really only acts on the advice of the Prime Minister.
Only the most extreme situations, such as a parliament that has "gone rogue", could the Governer General even consider intervening in the politics and policy of governance. The constitutional crisis that would ensue following such an intervention would make Pierre Elliot Trudeau's invocation of the War Measures Act in 1970 look trivial in its consequences.
So - let us presume that Michaelle Jean is a diehard separatist - what could she do? Not much, really. She might be able to refuse to sign a few pieces of legislation into law before the Prime Minister petitioned the Queen to remove her from office. Or, she might be able to funnel a few dollars from the Governer General's office to conspirators in Quebec for a while. (Until the Governer General's accounts were opened to the Parliamentary Accounts Committees that year).
One thing that is abundantly clear is that the Governer General's role is primarily symbolic in nature. Canada would have to suffer a crisis that would essentially be the breakdown of law and order in the nation before she could do anything significant. Although there is a great deal of innuendo about Mme. Jean's leanings lately, her expressed allegiance is to Canada. Since the bulk of the "evidence" being cited to associate her with Quebec Separatists ranges between 10 and 20 years old, I'm quite prepared to accept her at her word. People's political views and leanings change over time, and even if Mme Jean enjoys a glass of wine with sovereigntists from time to time, I don't believe that will stand in the way of her carrying out her role as the Governer General of Canada.