When Canada’s federal election came to a close this spring, the Conservative Party — which had been up 25 points in the polls as late as January — finished second to the Liberal Party. A plurality of voters cast their votes for former banker Mark Carney, hoping the technocrat could block Conservative leader Pierre Poilievre and stand up to Donald Trump.

Many voters who had previously backed the social democratic New Democratic Party (NDP) switched their support to the Liberals. In Ontario, the Conservatives flipped longtime NDP seats in working-class industrial hubs like Windsor and Hamilton, areas one might expect to break for the Left. Despite higher turnout, the NDP’s vote count plunged from 3 million votes to just 1.2 million. Haunting these electoral returns is the specter of dealignment, as working-class voters continue to respond to the Conservative message.

The explanation for these reversals in fortune may be familiar by now, but they still hold true: Justin Trudeau’s spring departure, combined with Trump’s attacks on Canada’s sovereignty and economy, transformed the electoral landscape. A rally ’round the flag effect took hold, polarizing voters around two questions: Who could best respond to Trump, and who offered a real break from the Trudeau era?