BTW -- the US military is actively moving to put more of their mission critical data in the cloud. But don't worry. They're gonna be super careful. [/s]
OK this is a subject I'm not totally ignorant on.
1. There will be NO classified data "in the cloud"
2. "the Cloud" is a bunch of different things to a bunch of different people and causes. No matter how you define it, you're both right and wrong.
The biggest cyber risk to US Security is the way Contractors and Vendors handle classified data...AND the ease by which PERSONS can be compromised.
The cure to most breaches is to go back to Executing those who provide classified data to unauthorized persons.
Execution is a great deterent.