Don't need to. The US already has legally binding and mutually respected treaties in regards to the US Canada border. They have made no such agreement with Canada to cede control of that border to a 'peace keeping' third entity. There is no state of war between the nation's or any sustained effort to change or ignore that border and the UN regards things as law that the US has not agreed to which would be incompatible with the agreements made in law, so what the fuck is really going on here.