Mr. Speaker, when people cross the border from Canada into the United States, they need to comply with the customs and immigration procedures of the United States. They can do that in the conventional manner in the United States after they have crossed the border—get in line and take their chances—or they can do it in a pre-clearance environment, before they cross the border, where they have the overall umbrella and protection of the Canadian Charter of Rights and Freedoms.
In the House of Commons on December 5th, 2017. See this statement in context.