North Korea’s leader pulled a dictionary word out of the 14th century to insult President Trump.

North Korean leader Kim Jong Un persists in testing nuclear weapons and missiles in defiance of the United States and the rest of the world. President Trump imposed new sanctions and threatened to destroy North Korea. On Friday, Kim upped the ante with a threat to test a hydrogen bomb over the Pacific for the first time.

Relations between the United States and North Korea have rarely been worse since the Korean War in the 1950s, when U.S. troops fought with South Korea against forces from the North.

Today the stakes couldn’t be higher. North Korea, an isolated nation ruled by a dictator, has an arsenal of nuclear weapons and missiles that can reach U.S. allies in the region, and possibly the U.S. mainland.

The rhetoric exchanged by Trump and Kim are the most bellicose ever between leaders of the two countries. Trump this week dismissed Kim as “rocket man” and threatened to destroy North Korea. Kim responded by calling Trump a “dotard” and compared him to a frightened dog. On Friday, Trump called Kim a “madman.”

Where does it go from here? Analysts say it is impossible to predict what two highly unpredictable leaders might do, but a number of options — from comforting to frightening — are possible:

Continued standoff

Under this scenario, the United States ratchets up economic pressure on North Korea. In response, Kim continues to test missiles, though stopping short of what he believes will trigger a military response. The heated rhetoric on both sides goes uninterrupted, resulting in a tense relationship that has persisted for more than a decade.