North Korea is positioned for a war as might be fought four decades ago with tanks and mass quantities of foot soldiers, none of whom are properly trained or equipped. They have a standing army of 1.2 million but most join to have three meals a day and a job. They aren't motivated to actually go into combat.
The US recently flew two B2 bombers within 50 miles of the border, a round trip of 6,500 miles direct. With the nuclear capacity of just those two aircraft, they could wipe North Korea off the face of the earth and they have no defense to prevent that from happening. They know that and all this blustering is just that - blustering.
the united states would win because north korea has no alies with anyone around them. and china and south korea would help the united states because south korea is our alie and china wants it money back so if we die they are out of luck
Considering North Korea would most likely have the backing of China, which no one seems to be taking into account, and that the UN would most likely bar the U.S. from using full military force, then it's actually possible they could win, and even if they did lose, we would take heavy losses.
Despite their shear numbers, they lack the firepower capable of standing a chance against us. They have only one nuke, we have a LOT. They have allies but not enough to pose much of a threat. Russia and China would likely stay out of the conflict. If anything, no doubt they would be they'd be starting the conflict which would also bring the UK, Germany, Australia, new Zealand, Canada, and all of OUR allies in to help. North Korea is biting off more than they can chew.