I have always been taught that the idea in Canada, the UK, and other Westminister-style Parliamentary democracies is that Parliament is sovereign and that the prime minister and cabinet must maintain their confidence to rule legitimately.
A recent Economist article on Brexit makes several references to how their fixed-election law ambiguously alters that:
[T]he Fixed-term Parliaments Act of 2011 upturned established conventions on confidence votes within the Commons, leaving confusion among MPs over both how to bring a government down and what happens when one falls. And the quirks of British parliamentary procedure provide various ways in which a sufficiently bloody-minded prime minister might force a “no-deal” Brexit without a majority in Parliament. This has all the makings of a constitutional crisis.
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The Fixed-term Parliaments Act got rid of the power that prime ministers had previously enjoyed to call an election at any time, thus reassuring the Lib Dems that the Tories would not cut and run as soon as they fancied their chances.
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The country may thus see a new conflict over where sovereignty lies—the constitutional question which, above all others, Brexit has dragged into the light.
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Some of the subsequent mess rests on the back of the Fixed-term Parliaments Act of 2011. Before this a prime minister whose flagship legislation was voted down—just once, never mind repeatedly—would have been expected to call an election. If he or she had not, a vote of confidence would have followed which a minority government would have been near certain to lose. The 2011 act replaced this convention with statute which says that a lost confidence vote triggers a two-week period during which any mp can attempt to win the backing of the Commons and form a government to avoid an election. When asked what this would actually look like, the clerk of the House of Commons responds: “I really don’t know—I don’t think anybody knows.”
It seems remarkable that an ordinary piece of legislation can muddy or upend the most important constitutional convention in Westminister democracies — the confidence convention — and that the legislation in turn was to solve a short-term coalition management problem.
The article also discusses another change that got limited consideration but which has important and open-ended effects: “The hurried inception of the Supreme Court was, in the mocking words of its former president, David Neuberger, ‘a last-minute decision over a glass of whisky’.”