"Lying is wrong, except in three things: the lie of a man to his wife to make her content with him; a lie to an enemy, for war is deception; or a lie to settle trouble between people (Ahmad, 6.459. H)"This is why, for decades now, Iran has done nothing but lie to us about their nuclear program. Consistently, they have told us that it is for the peaceful use of producing electricity and in aiding medical treatment. They have signed several agreements while denying their nuclear weapons program. And, there is no reason to believe they aren't lying to us now in our current round of negotiations.
Iran Nuclear Program: http://en.wikipedia.org/wiki/Nuclear_program_of_Iran
Iranian Embassy Webpage: About Iran's Peaceful Nuclear Activities: http://iranembassy.no/en/6.htm