2. The U.S. - Canada lumber battle
NAFTA isn't the only sore area. In 2002, the U.S. slapped a roughly 30% tariff on Canadian lumber, alleging that Canada was "dumping" its wood on the U.S. market. Canada rejected the claim and argued the tariff cost its lumber companies 30,000 jobs.
"It was a very sour point in Canadian - American relations for quite a while," says Tom Velk, an economics professor at McGill University in Montreal.
The dispute had its origins in the 1980s, when American lumber companies said their Canadian counterparts weren't playing fair. Canada subsidizes lumber companies because the government owns many of the lands where the wood comes from. That subsidy -- on top of Canada's huge lumber supply -- allows Canada to price its lumber below what U.S. companies can charge.
The WTO ultimately denied America's claim and the two sides came to an agreement in 2006 to end the tariff so long as prices stayed within a certain bracket.