A20. In theory, an MLA can vote however they want.
But in Canada generally, and certainly in Nova Scotia, we have tight caucus discipline. The members of a caucus almost always vote the same way. But why? Is it loyalty? Is it discipline? Is it fear?
In my experience, the main reason that caucus members vote together is that they believe they can get more done as a team than as individuals. Caucus unity is more likely to satisfy past voters and impress potential voters. Caucus disunity makes it look like the party doesn’t know what it’s doing and would not be capable of forming a government.
Another reason is that caucus members (usually) genuinely agree with each other. People often join a political party because it has a philosophical foundation (sometimes called “ideology”) that the person shares. The MLAs in a party caucus are (usually) in broad philosophical agreement with each other.
Another reason is that caucus members may be punished if they step out of line.
The way politics is practiced in Nova Scotia, caucus members can say whatever they want behind the closed doors of a caucus meeting. Once they emerge, though, they are expected by their party leader and their caucus colleagues to conform to whatever decision was reached in the meeting.
Sometimes a leader will inform the caucus that s/he will permit caucus members to vote any way they want. This is called a “free vote”.
Sometimes a leader will inform the caucus that s/he expects all members of the caucus to vote the way they’re told, regardless of their personal views. This is called a “whipped vote”.
For the reasons I’ve given above, whipped votes are actually quite rare. Caucus members almost always believe they’re better off, in the long run, if they vote together. They don’t have to be whipped.