The president would have to rely on his “51st state” to track Chinese and Russian missiles that could come at the U.S. from over the horizon.

Canadian Prime Minister Mark Carney says his government is talking to the U.S. about joining President Donald Trump’s future Golden Dome missile defense program.

PM Mark Carney's office says there are "active discussions" on the Golden Dome, but it's too early to say how Canada would join or pay in.