I think Iran is trying very hard to get a nuke. I think they wish to use it on Israel. I don't think they care who the President of the USA is when they do it. I think, they are trying to please Allah, and not worrying about the rest of the world.
As for terrorism in our immediate future, I see it going both ways. Less terror attacks while he is in office, because of a false peace being started, where terror groups use the peace time to prepare for their next major offensive. While the west relaxes on it's laurels. Or the terror attacks increase and escalate because of a lack of retaliation led by the USA.
There is a third choice... Obama may surprise many in this nation, by not taking terror attacks sitting down. Hey, it could happen.
As for RIP USA, you may be right, but your reasoning is flawed. Iran would not withhold a nuke for fear of ruining Palestine. The ground means nothing to them. Killing Jews is something that they believe in.
It is time to wait and see. But I don't think Israel is going to take any of this sitting down.