Cohen headed Pentagon during the second Clinton administration, an era which saw the Cold War fading away, apart from Nato expanding to include some erstwhile Eastern Europe Communist nations and the US’s intervention in Bosnia.
"There is no fixed end to the war on terror. War on terror is a misnomer. To use Kennedy's phrase, it's a long twilight struggle," Cohen, who now heads The Cohen Group, said.
He said China's unveiling of stealth fighters -- advanced aircraft that can go undetected -- did alter the regional security balance. So, India should try and acquire stealth capabilities from US, he said.
"You should be acquiring them. The US would be willing to engage with you on that but for that we need to have a strong and stable defence cooperation," Cohen said.
Asked if the war in Iraq was one of great folly, even if the Afghanistan war was one of necessity, Cohen said: "My position was... We felt Saddam (Hussein) was contained. There's no reason to go into Iraq, unless Saddam went into Kuwait again or something like that."
So, what changed vis-is-vis Iraq?
"9/11 and change in the administration (from Clinton to Bush). There were some miscalculations."