DETROIT – Canadian officials are preparing to move against a group of truck drivers who have blocked the nation’s busiest border bridge between the U.S. and Canada in protest of the country’s Covid-19 vaccine mandate. The blockade, now in its fifth day, has brought traffic to a halt over the Ambassador Bridge between Detroit, Mich. and Windsor, Ontario, which accounts for a quarter of goods traded between the two countries. Ontario Premier Doug Ford Friday declared a state of emergency in the Canadian providence, saying at a news conference that authorities plan to enact temporary orders that will fine protesters...