President Trump has opened a new front in the US-Canada trade war. …But not on softwood lumber. Like other goods already subject to Section 232 tariffs, softwood got a pass. That exemption is more revealing than the tariffs themselves — and it points toward a deal that has eluded both countries for four decades. The US imports about a third of the lumber it consumes, and Canada supplies roughly four-fifths of those imports. …American mills are already running at roughly two-thirds of capacity, and output has been flat for years — tariff protection has not built the industry it was meant to build. …Four decades of duties changed the supplier, not the dependence. …The 2006 Softwood Lumber Agreement supplies the model: export charges or volume restraints that stabilize trade without either government surrendering its legal position. A modern version should go further… creating faster dispute resolution before disagreements spiral into another decade of litigation.