The moral burden upon the shoulders of federal legislators is an enormous one, but the right decision – one that eschews considerations of partisanship or career prospects for the greater good of American and global security – is clear. Unless Congress acts, Iran is set, within 15 years if not sooner, to become a nuclear-armed power that dominates the Middle East, likely dragging American troops back into the region and setting off conditions that could precipitate the kind of horrendous war that President Obama says, with genuine sincerity, he wants to avoid.