Washington must either either start a war in Korea, or gets faced down by the North, its carriers ignored, its bombers "sending signals" and making "shows of force" without result. For the empire this is a loss of face and credibility, and an example to others that America can be challenged.
Iran has not caved to Washington's threats and sanctions and clearly isn't going to. Another strategic loss, a big one, unless–the hawks seem to think–remedied by a war. Iran wants to trade with Europe and Europe likes the idea. Worse, Iran is becoming a vital part of China's aim to integrate Europe and Asia economically. To the empire this smelñls of death. The frightened grow desperate.
China shows no signs of backing down in the South China Sea. For Washington, it is either war now, when thinks it might win, or be overshadowed as China grows.
Russia has irrevocably gotten the Crimea, is quietly absorbing part of the Ukraine, and looks as if its side is going to win in Syria. Three humiliating setbacks for the empire. Loss of control of the Mideast would be a strategic disaster for Washington.