On Thursday a former premier of Alberta, Rachel Notley, announced “with mixed feelings” that she is resigning her seat in the province’s legislature at the end of the month. Her feelings might well be mixed, and that’s a decent description of how Alberta feels about Rachel Notley. The judgment of history will emphasize her extraordinary feat in winning an Alberta general election for the New Democrats, something that had previously been unthinkable, and establishing the party as a credible governing alternative when the province really, really needed one.