The concept of a mandate is pretty common in Canadian politics; isn't it in the US?That's absurd.
Let's say a typical politician runs for office to do what he (or she) believes is right.
If you say he has no "mandate", this doesn't mean he's morally required to no
longer pursue what he believes is right. He either succeeds or he doesn't.
A bunch'o crestfallen tantrum throwing losers won't stand in his way.
The idea is that an elected representative is supposed to represent the interests of the whole people, not just the people who voted for him, and the popular vote (along with voter turnout, etc.) is an indication of how much the people's interests are served by his platform.