The resignation of Alison Redford from the premiership of Alberta is an arresting reminder that prime ministers and premiers can suddenly lose the confidence of their own caucus, even in an era in which executive political power is heavily concentrated in the first minister's office.
In October, 2011, Ms. Redford won the leadership election of the Progressive Conservative Association of Alberta, in part because many Albertans took out party memberships just in order to vote in the race. Some were by no means typical, core Conservative supporters, for example, schoolteachers and labour-union members.
Later, in the general election of April, 2012, the more militantly conservative Wildrose Party might well have won, but a number of extreme statements by Wildrose candidates turned the tide back in favour of the Progressive Conservatives, who won 61 out of 87 seats.
Ms. Redford had had little support in the Conservative caucus, in the 2011 leadership campaign. That was all the more reason why, as premier, she should have tried to put down stronger roots in her own party, cultivating its MLAs and riding-association presidents.
She governed moderately; there was little sign of what red-meat conservatives would call Red Toryism. Ms. Redford worked hard to advance the long-term interests of Alberta and its oil-and-gas economy, supporting the Northern Gateway and Keystone XL pipelines. For example, she made an effective presentation to the liberal Brookings Institution last April.
The middle course that Ms. Redford tried to take in government spending, neither austerity nor extravagance, may have estranged different constituencies on right and left. That partly explains her current low standing in the polls, less than 20 per cent approval. But she was strangely undiscerning in the handling of her travel expenses and in her failure to connect with Conservative MLAs.
The province's general election is expected to be two years away. The polls could easily have changed; Ms. Redford's fall in mid-term is absurd as well as tragic. But the caucus revolt had gone so far that recovery was hardly possible. First ministers of Canada, beware.