Canada’s recently an­nounced second at­tempt to allocate dairy tariff quotas shut out most U.S. firms, providing only a fraction of the access promised in the U.S.-Mexico-Canada Agreement (USMCA) on trade, Reuters reported last week.

“Under USMCA, Canada agreed to open up its market to U.S. dairy products, and dairy farmers expect to have the market access benefits they were promised,” said Doug McKalip, chief agricultural trade negotiator for the U.S. Trade Representative’s (USTR) office.

The USTR on Jan. 31 requested a USMCA dispute settlement panel for the second time,...