United States Trade Representative Katherine Tai says the status of access to Canada's dairy market remains a "source of great frustration," which, along with the decades-long softwood lumber dispute, represent "fundamental differences" between the Canadian and American approaches.   Another provision of the Canada-U.S.-Mexico Agreement (CUSMA) that was seen as a win by the Americans were changes to access to Canada's dairy industry. Tai challenged Canada's interpretation of the deal's provisions, arguing it was not properly implementing them.

A dispute panel found in January that Canada was not living up to its promises under the deal, and the Americans claimed victory. Canada has proposed a new import allocation system, but it's been criticized by U.S. producers. The dairy industry in Canada has defended this country's ability to set its own import framework.

But Tai told Barton that improved market access "has not been realized," which was "a source of great frustration" for American dairy farmers and elected representatives who supported CUSMA in part because of the dairy provisions.

Canada has launched a challenge to existing U.S. duties on Canada softwood under the new North American free trade deal's dispute resolution process. It's just the latest development in a fight that has lasted for decades.

This is an excerpt from the CBC news.