Gerard Comeau, a retiree living in rural New Brunswick, never thought his booze run would turn him into a Canadian hero. In 2012, after Comeau had driven to Quebec to purchase cheaper beer and crossed back into his home province, police officers participating in a low-stakes sting operation tailed and detained him, confiscated his haul, and levied a fine of less than $300. Countries routinely engage in trade wars and erect barriers to protect domestic industries from foreign competition. Comeau, however, was detained by the full force of the law for engaging in commerce with a Canadian business on the other side of a domestic border. With Comeau's story as its starting point, Booze, Cigarettes, and Constitutional Dust-Ups tells the fascinating tale of Canadian interprovincial trade. Ryan Manucha examines the historical, political, and legal forces that gave rise to the regulation of interprovincial commerce in Canada, the trade-offs that come with liberalized domestic free trade, and Canada's enduring pursuit of economic union. The pandemic laid bare the vulnerability of global supply chains, the fickleness of foreign trading partners, and the surprising slipperiness of domestic trade. In a global climate of increasingly isolationist geopolitics, the history and possibility of Canada's economic union, quirks and all, deserve careful attention.