Note: this isn't a dig at UK govt or promoting other systems. Not even all that much at Truss - I'll add another PM from a different ideological lean if representative of issue.
Just a question about this particular effect in parliamentary systems.
Let's take two cases, where a new leader was chosen to replace a party's ousted leader:
Liz Truss is appointed PM after 160000 registered Conservatives vote. Of those she got 57% of the votes cast: barely 81k people to get the leader of a country of 67m after taking over from an already unpopular Boris Johnson, with essentially a promise to double down on hardline Conservative policies.
Danielle Smith, in Alberta, Canada gets 40k votes in a province of 4.5m people. She took over from PM Jason Kenney who was widely panned for covid mishandling but, to many people, Smith very much looks like she would have done significantly worse. In a province with a large Ukrainian diaspora, she's on the record stating Putin should get bits of Ukraine.
Smith won by motivating a base of disgruntled Albertans who thought pandemic restrictions unnecessary, cheered on angry truckers' blockades, and believe Prime Minister Justin Trudeau is out to destroy the province's energy industry.
It was a campaign of anger, grievance, conspiracies and retribution — and her supporters loved it.
She promised to fire the board of Alberta Health Services, get rid of socialist public servants and, most notably, introduce an Alberta Sovereignty Act that she says would allow Alberta to ignore federal laws and court decisions deemed to be un-Albertan.
Danielle Smith is new UCP leader — and Alberta's next premier (new window) The party says 82,000 mail-in and in-person votes were cast. About 124,000 members were eligible to vote.
Smith didn't win a landslide: just 42,423 votes. In second place, Travis Toews with 36,480. But it was more than enough.
It's hard to see any election in which these people would be chosen by the larger electorate, rather than a small majority of registered voters from their party. This seems problematic, democracy-wise. For better or worse, Boris Johnson and Jason Kenney were given the nod by electors at large.
Now, I know that people will say, rightly: people didn't elect Boris Johnson, much as Johnson liked to claim a personal mandate.
But that is ignoring that people do in fact vote based on how their perceive a party's leader at election time, because a party's leader has a large say in that party's platform. UK voters rejected Corbyn and Labour's ejecting him afterwards as a result is an implicit recognition of this fact.
Is this occasional tension between a replacement leader's unpopularity and a parliamentary system innate, built-in and unavoidable? Can different procedures and electoral systems avoid it, while remaining parliamentary in nature?
Do secret ballots during votes of confidence modify this? Or is this phenomenon linked to parliaments which only have a limited number of parties? I expect things would look different in Israel for example.
p.s. with my province's premier, John Horgan, leaving for health reasons, BC is faced with the same situation, giving me extra "skin in the game" to be asking about this. Fortunately, BC's provincial NDPs are a reasonable enough lot, making it unlikely we'll have a dysfunctional successor (David Eby has been all but chosen).