The Superior Court of Quebec on Thursday upheld the constitutionality of a law passed by the National Assembly that reaffirmed the province's right to self-determination. 

The law was passed in response to the federal Clarity Act, which adopted in 1995 after Quebec's failed sovereignty referendum. The act stated that in order for a province to begin negotiations on separation, a referendum would have to come with a clear question and a clear majority.

The Quebec government, then led by Lucien Bouchard, responded by passing Bill 99 in 2000, which stated that in a referendum, the winning option is one that "gets the majority of the votes declared valid," or 50 per cent of the votes plus one vote.

In 2001, Keith Henderson, the then-leader of the now-defunct Equality Party, issued a legal challenge to the bill, saying it was unconstitutional. 

The Quebec Superior Court began hearing the challenge to Bill 99 a little over a year ago. In the ruling, the judge said the "50 per cent plus one" formula is legal under the Canadian constitution. 

Henderson said he's unsure if he'll appeal the decision. 

The president of the Societe Saint-Jean-Baptiste, Maxime Laporte, called the decision a major victory for Quebec nationalists.