Canadian here. Although my personal politics tends to be CENTRE-right (note the capitalization) and favouring market forces, I do see some merit in supply management to avoid the extreme pain being experienced by the American dairy farmers mentioned in the article. Yes, we mostly do prefer supply management, paid for by dairy consumers, than massive subsidies, paid for by all taxpayers and leading to wasted output.

For details, read Wikipedia [0]. Some quotes:

- High (tariffs) are only placed on imports above the quota, not on all the dairy products sold to Canada.

- Canada's milk quota system is butterfat-based so the highest TRQ is on butter at 298.5%.

- By 2018 the United States's quantitative (tariff) threshold for the import of milk products is 3% and Canada's is 10%.

- designed to prevent shortages and surpluses, to ensure farmers a fair rate of return and Canadian consumer access to a high-quality, stable, and secure supply of these sensitive products.

Mr T, in his incendiary speeches to his tribe, was selective with his facts. The 300% tariff does not apply to all dairy; only butter and only when exceeding USA's quota (Canadian farmers who exceed their quota cannot sell at all). The threats and beatings delivered by Mr T's negotiators did "open up" the Canadian dairy market a little, but supply management is still intact and "diversification" is now on the minds of many Canadians.

[0] https://en.wikipedia.org/wiki/Supply_management_(Canada)