Serena Williams makes winning comeback in doubles with Canada's Victoria Mboko

As Albertans prepare to test the idea of leaving Canada this coming October, their most attentive observers may be found about 3,500 kilometres away in Quebec, where sovereigntists will be studying the outcome for lessons into their own long-stalled project. Strictly speaking, Alberta isn’t holding a referendum on separation. Voters are being asked whether the province should begin the legal process that might lead to a binding referendum. In other words, it’s a pre-referendum referendum. A question about a question. That detour reflects the constraints of Canada’s Clarity Act,...