Justifying the move as a step to keep America safe is the right move in this political context. America is generally fearful right now, so Obama's political adversaries will attack this move as eroding the safety the prison system attempts to maintain.
"My job is to keep Americans safe" is an acceptable justification for limiting solitary confinement. It would not be an acceptable justification for extrajudicial killings.
"My job is to keep Americans safe" is an acceptable justification for limiting solitary confinement. It would not be an acceptable justification for extrajudicial killings.