There's no doubt that part of this just does have to do with internal politics. However, I think, from lessons looking at what has often befallen the Jewish people, that when somebody does threaten to kill you, you do have to take that seriously. That's not to say that you immediately pre-empt this with severe military strikes, but it does mean that you have to spend a little bit of time investigating whether there is some truth. Ideologically, both in terms of their past efforts, as well with regard to sponsoring terrorist groups that are very busy trying to do damage within Israel, there is good reason to believe that they would be serious.
If you're asking whether they would be prepared to launch some sort of nuclear strike and then risk very severe retaliation, there is a question about that. This really goes into the discussion of are they rational or aren't they rational.