It's a threat to world peace, Dan, especially South Korea and Japan. So, yes, it is also a threat to the US.
On a news clip this week there was rioting in Iran following Saudi-Arabia's execution of a Muslim cleric. Among other things they burned an American flag. It seems America is held to blame for everything that happens in the world from Saudi atrocities to the abandoned trekkers on Mount Kinabalu. So, yeah, Kim Jong Un and his gormless crew will most certainly blame America for their problems and may look at you with anger as they consider where next to test their bomb.