Canada staged a large-scale diplomatic deployment this week in preparation for a U.S. presidential election of more consequence than usual.

More than a dozen Canadian diplomats posted in various U.S. cities came to Washington to meet with scores of American lawmakers on Capitol Hill.

Looming over their visit was the potential return of Donald Trump to the White House. In particular, there’s one Trump policy they’re watching warily this year.

The former president has promised a worldwide tariff on imported goods if he wins. This would be stricter than any trade policy from his first term.

Trump has offered minimal details about the policy in his campaign literature and in media interviews but has said he envisions a 10 per cent global tax.