After the US had a shot at taking out Kim Jong Un, North Korea changed its launch tactics

When North Korea test-launched an intercontinental ballistic missile on July 4, the US reportedly had observed Kim Jong-un for 70 minutes before the missile took off.

A US official let that detail slip to the Diplomat's Ankit Panda, possibly signaling that the US could have struck the missile site and killed Kim, who was standing right there.

But when North Korea last tested a missile that experts say could hit most of the US mainland, they did it in the dead of night from a previously unknown launch site with several Kim Jong Un lookalikes walking around the site.

According to Jeffrey Lewis and Aaron Stein, missile proliferation experts who host the Arms Control Wonk podcast, this could very well have been a signal to US forces. 

"Reports are it was launched from an unusual location in the heart of the country that we'd never seen it before... I think that was response to stories that we saw the missile 70 minutes prior to its launch," said Lewis.

"This looked more operational," said Stein. "It would be launched from a place we might not necessarily think they would launch from or have ever seen evidence that they might launch from, and they can do it at any time of day."

Notably, the ground-based mid course defense, the US's primary line of missile defense, has never been tested at night.

Essentially, if North Korea really wanted to hit the US with a nuclear missile, a snap launch in the middle of the night like the one they displayed on Friday would work best, and the US would face a much harder task in stopping them.