So, is it the result of bilateral negotiations, the 'threat' of US going to war against them or a combination of both?
The bilateral negotiations look good on paper, but look how well it worked in Iraq. I figure that Europe made some concessions behind the scenes, and Iran will continue their program secretly. I also think that the war in Iraq has got to make them a little nervous that they could be next.
The situation is in no way resolved yet and I await the actions the Iranians will take in the following weeks and months.
A threat of a US invations am I pretty sure played no part what so ever. The US lacks the military capacity to conquer and keep such a large and impassable country as Iran. Funny as it may sound the threat of economic sanctions is a greater threat than military invation. The Iranian population is very young and unemployment is a serious threat to stability. An economic setback could weaken the government, a fact it is well aware of.