TORONTO (AP) — It started with President Donald Trump's attacks on Canadian dairy farmers. Then Washington slapped tariffs on Canadian steel, citing national security. There was that disastrous G-7 summit in Quebec. Now it's a new North American free trade agreement that excludes America's northern neighbor.

Canadians are stunned by the repeated broadsides from what has long been their closest ally and some have even begun boycotts.

"Everybody is afraid," said Margot Lajeunesse, who helps run a family-owned bistro in Quebec. "We depend a lot on the U.S."

About 75 percent of Canada's exports go...