To start, it's easy to see why this is momentus. While the previous government was not known to be friendly toward women in politics, Canada has in fact had a pretty long history of women's absence from cabinet. 27 per cent of the Liberal MPs elected to Parliament were women - that's 50 of the 88 female MPs elected. This broke a few records, and the cabinet announcement is really an achievement that goes well beyond this.
However, it's perhaps a bit more difficult to see this event as merely a requirement. The time for this has, to some degree, come and gone. Canada ranks poorly in terms of female representation in federal politics, below the 30 per cent threshold that is encouraged by the United Nations. The fact that it took until 2015 to have anywhere even close to this level of parity is, frankly, rather embarrassing. Trudeau's decision should be lauded, but it is nowhere near as progressive as some people are making it out to be.
It's worthwhile noting that there are existing quota systems in play in federal government. The most evident are regional differences, language, and affiliation. A good cabinet has largely been one that is meant to look good on paper, so the fact that so many people are bent out of shape about Trudeau's choices not being about merit are rather misguided. In fact, this truly reinforces the idea that quota systems are short-term solutions, because eventually we come to expect a certain diversity.
As such, I'd like to briefly outline the importance of affirmative action. There was barely an increase over 2011 in terms of women elected to the House of Commons. However, the media will have you believe that the 1 percentage point increase is a massive coup. This, as mentioned above, plays out both negatively and positively depending on people's values (to scare or encourage). But the idea should functionally be that a cabinet with parity should encourage more women to become engaged in the political system and, perhaps more importantly, it should convince the public that women are in fact capable of holding a portfolio and delivering like their male counterparts.
I'll leave you with an important notion: that diversity will lead to a greater degree of experience, a sharing of values, and hopefully better governance. Let's see what the next four years will hold.