(CNN) -- Alan Eyre, a former senior US diplomat and member of the team that negotiated the 2015 nuclear deal with Iran, told CNN's Anderson Cooper that the United States 'has not tried diplomacy in a serious or sustained way' in dealing with Iran, noting that 'unfortunately at this point, time has run out for diplomacy,' and asserting that 'we are stuck in what we are in, a death spiral,' as he put it.

Eyre said: 'I still argue that we have not tried diplomacy in a serious or sustained way. Initially we tried, and we were waiting for Iran to surrender. Then once the war started, we still believed that our superior military dominance would translate into strategic success. That did not happen. I think it is unfortunate at this point that time has run out for diplomacy. Even the best diplomats, I don't think they can achieve victory from this.'

The former diplomat noted that 'unfortunately, at some point before the bombs started falling, there was a chance if we had been more consistent and steadfast, to stop, you know, all the real social media posts and inconsistent red lines, but we missed that opportunity.'

He also stressed that 'now we are stuck in what we are in, a death spiral similar to M.C. Escher's 'Whirlpools' painting, with military attacks, de-escalation, and more military attacks.'

For his part, CNN political analyst Karim Sadjadpour said in the interview that 'there are no magic solutions here. There are no quick fixes. President Trump first sought a quick fix, believing that American bombs could change Iran's policy. That did not work. Then there was an attempt with American incentives and American bribes to try to change Iranian policy. That did not work.'

Sadjadpour affirmed that 'what we know over the past 47 years is that this regime has agreed to a meaningful settlement only on two or three occasions, and that is when it feels existential pressure coupled with a kind of face-saving diplomatic exit,' adding: 'And at this moment I don't think they feel existential pressure, and there is no face-saving diplomatic exit.'