I think it is important to remember these tests are in a highly controlled environment, but I think without a doubt it does increase confidence in the only system the US currently has to defend against the North Korean ICBM threat:
The Pentagon announced that the United States on Tuesday tested for the first time its intercontinental ballistic missile defense system, a system designed to foil the types of missiles Kim Jong-un and North Korea have been looking to develop.
According to Reuters, the Ground-based Midcourse Defense (GMD) interceptor test took place today at Vandenberg Air Force Base in California.
The test was a success.
“We improve and learn from each test, regardless of the outcome. That’s the reason we conduct them,” Pentagon spokesman Captain Jeff Davis said Tuesday. “The system that we test today is a developmental system that’s being flown for the first time and we look forward to understanding the results so we continue to mature the system and stay ahead of the threat.”
While the test is said not to be just about North Korea, the timing indicates that it has everything to do with Kim Jong-un’s recent ballistic missile tests. [Atlanta Journal Constitution]
That is where many in the media are getting it wrong, these tests are planned out and scheduled years in advance. The fact North Korea fired ballistic missiles recently as the Pentagon has said had nothing to do with the timing of the test. Plus this system could not shoot down those missiles anyway. GMD is only used to defend against ICBMs. The shorter and medium range missiles that North Korea has been firing recently would be defended against by the THAAD and Patriot missile defense systems.
You can read more about this history of the GMD program at Defense News.