Concession is not required by law or mentioned in the U.S. Constitution, but it marks a tradition of sportsmanship among presidential competitors that helps maintain the balance of political discourse. 

At a news conference in Ottawa on Monday, Trudeau said Canadians should trust the American electoral process 'as it has unfolded.'

'I think what's needed now both to fight the pandemic and to carry on with the United States as the great success story that it is, is calm, resolute leadership,' Tory said.