The United States and Mexico can’t exclude Canada from entering formal trade negotiation with China, Agriculture Minister Lawrence MacAulay says — despite an ongoing global trade war and questions about a clause in the trilateral trade deal. MacAulay was asked by reporters on Monday about a clause in the United States-Mexico-Canada Agreement (USMCA) that allows any member of the trade pact to veto a free trade agreement with a “non-market economy” — including China.A non-market country is a country that doesn’t operate on free-market principles that go beyond traditional trade protections. As a result, pricing doesn’t reflect the true value of a product.