Perhaps, the reason to be concerned in this case, is one nation's ability to alter the atmosphere of another nation. For example, should US be able to deploy persistent array of clouds that block sunlight, that can significantly impact a nation's ability to exist. What if this cloud can stop vegetables from growing, drop your temperature by 10 degrees, suck out vitamin D from your system and get your really depressed? Possibilities are endless, and as much as it sounds futuristic, it's not. Short-term alterations to the atmosphere are a perfect weapon.
