North Korea cutting off all road and rail access to South Korea is a pretty big deal. It’s like they’re drawing a line in the sand and saying, “That’s it, we’re done.” Kim Jong-un isn’t even pretending to want reunification anymore, and now they’re fortifying the border? While these moves might be more about sending a message than starting an actual conflict, it’s still pretty concerning. With the U.S. already busy in Iran and Ukraine how thin can they get stretched?