It might seem more like a comedy than a true story when it comes to the nuclear launch test the North Koreans decided to hold on April 12th 2012. US, Japanese and South Korean officials were extremely angered over the talks that North Korea would test launch a nuclear weapon. In fact there was quite a bit of concern from all three countries that something like a test launch would be extremely dangerous and could lead to extreme political issues with North and South Korea tensions rising; however, after the launch it may seem that the worry was for nothing.
The US military moved into position to help South Korea if needed, while remaining in Japan to conduct talks about its own military base move on hold to Guam and other areas of Japan from Okinawa. Japan announced after the test launch that the rocket flew for perhaps a little over a minute before it fell. South Korea stated that the missile not only flew for a short period of time, but also destructed into several pieces before it fell. The debris fell into the sea on the North Korean side, just short of falling into Gunsan Sea on the South Korean side.
This was not the only test North Korea has undertaken in the last ten years, but many of those other tests also failed, with only a few falling near the sea around Seoul. The US military will stand down, but be on hand for any help that is needed should tests be conducted again.