What the Syria debacle taught Iran is that Obama is so desperate to avoid military entanglements, especially if they frame actions in ways that make American armed might look like an indispensable 'good' [the whole point of 'leading from behind'], that he will agree to anything just so long as it contains components that he can sell as viable regardless of whether or not they actually are. Any objective, informed observer knows that Putin cannot be trusted, has interests which conflict with American interests and that his 'plan' is more scheme than anything else and will achieve little or possibly none at all of the good it promises - yet Obama readily went along.
The questions to ask: is Obama a naive fool or is it that he feels or imagines that he somehow can avoid the negative consequences of his actions - and when we say 'he' does that mean the country and his party or does it just mean his own political self? He doesn't have to run in another election, so there's that - and he no doubt has some idea of a legacy he wants to protect - but does that mean he doesn't care about the fortunes of his party and that he feels 'peace at any cost' is a plenty good thing to be known for? Dunno. Are we possibly seeing here the wholly pernicious effects of media bias insomuch that Obama maybe believes that the liberal elite is so willingly blind to his flaws and so driven to burnish his image no matter what that he can get away with anything? Possibly. But that still leaves the vexing question: what about harm to the country? Can't be he doesn't care [we're hoping, anyway] - so it's got to be either he doesn't see it [naive], refuses to acknowledge it [wishful thinking], or has a different notion of what actually could be considered 'harm' as far as the country as a whole is concerned [all of the above - in short, he's an uber liberal].