James Clapper: “I often wonder whether Mr. Putin will rue the day he decided to come back.”

Ties with Tehran offer some regional governments a means of staking an independent position on Iran, thereby mitigating its isolation while also attempting to extract Iranian financial aid and investment for economic and social projects.

He has a grievance eating at him for about 20 years and has made a decision, I think, to try to redraw the national security architecture of Europe.

I think he's trying to erase any vestiges of as much as he can of culpability that people that were caught up in this investigation.

I think it has more to do with the psychology of Putin, and Russia. And he needs to assure his own people, Parliamentarians, he was talking to, and for that matter, himself, that Russia is still a great power.