I am skeptical that the Iranians are really going to end their program or even freeze it. A nation doesn't just go from chanting "death to America" every day (and actually, they're still doing that) and increasing their antagonism against the Sunnis (and they're still doing that) to signing an agreement of this sort. The economic sanctions certainly forced them to make some concessions, but I think they are playing for time.
If it turns out that my skepticism is misplaced, Obama might yet be able to point to some concrete achievement of his Presidency. If, on the other hand, a few years from now we have a nuclear Iran, a nuclear Saudi Arabia and growing tensions in the region, his failure will be total and his legacy will be one of unremitting failure. I hope, for our sake rather than his, that his legacy will be of at least some foreign policy achievements.
ἡ δὲ κἀκ τριῶν τρυπημάτων ἐργαζομένη ἐνεκάλει τῇ φύσει, δυσφορουμένη, ὅτι δὴ μὴ καὶ τοὺς τιτθοὺς αὐτῇ εὐρύτερον ἢ νῦν εἰσι τρυπώη, ὅπως καὶ ἄλλην ἐνταῦθα μίξιν ἐπιτεχνᾶσθαι δυνατὴ εἴη. – Procopius
Ummaka qinnassa nīk!
*MySmiley*