Obama, it appears, is a leader who capitulates often and falls prey to foxes like Putin and Assad. They simply deceive him. The result is that the leader of the free world is incapable of keeping his promises.
Take, for example, the Syrian chemical weapons affair. It was Obama, after all, who set the red lines. He was the one who said that if Assad used chemical weapons, all lines would be crossed and the US would intervene in what was going on in Syria. But he was also the one who refused for a long time to believe that the tyrant had attacked his own people with chemicals weapons.
When he finally accepted the world's outcry and decided on a strike – he fell for the shady plan concocted by Putin, an agreement devoid of any meaning which gives no peace or stability to the region. To put it simply, Obama did not keep his promise regardless of all explanations and interpretations surrounding that capitulation. It's clear to all that Assad will not give away all the chemical weapons in his possession.
If Putin and Assad are successful in fooling the American president, the Iranians will most certainly succeed in doing the same thing. Indeed, it is a grim reality when the man heading the strongest power in the universe is revealed as a person with excellent speaking skills but a weak character.
The only conclusion from all of this is that Israel must be concerned about Obama's promise. Unfortunately, the problem is not the American president's intentions. It's just his character which fails over and over, for "the spirit is wiling but the body is weak."