2/ International reactions would be swift. NATO would face a crisis, since Canada is a member, but the aggressor is the U.S. France, Germany, and the UK might condemn it but hesitate to intervene militarily. Meanwhile, China and Russia could exploit the situation—Russia seeking concessions in Ukraine or the Arctic, China expanding in the Indo-Pacific. Economically, it would disrupt supply chains, spike energy prices, and unsettle global markets.