OTTAWA, ONTARIO — Canadian Prime Minister Justin Trudeau on Monday invoked the never-before-used Emergencies Act that gives his government the power to prohibit public assembly and travel in response to the weekslong trucker protests that have brought the country’s capital to a standstill.

The extraordinary powers give the Liberal leader 30 days effectively to shut down demonstrations that began in Ottawa but quickly spread across the country and the border to protest all manner of COVID-19 restrictions.