TORONTO (AP) — First U.S. President Donald Trump attacked Canada on trade. Then Saudi Arabia punished it for speaking up for human rights. Now China has the country in its cross-hairs, detaining two Canadians in apparent retaliation for the arrest of a top Chinese tech executive on behalf of the United States.

Canada is caught between two super powers and taking the punishment — and its ally to the south has been conspicuously absent in coming to its aid.

"We've never been this alone," historian Robert Bothwell said. "We don't have any serious allies. And I think that's another factor in what...