Iran, as you're no doubt aware, has no interest in a nuclear weapon because having one would be "against their religion." Because of this, you should have no concerns about the United States lifting sanctions in exchange for...um...helping them get that bomb they don't want.
Unfortunately, there are a few things that aren't against their religion. Chief among these is "working to destroy Israel by funding terrorist organizations."
As the Telegraph reported this weekend, at the same time America's "leaders" were helping Iran achieve their nuclear dreams, Iran was busy helping Hamas rebuild their tunnels into Israel.