There's a load of information out there and everyone, including the US Govt, knows that Israel has nukes and has had them for a considerable period.
TBH I don't blame them, nor do I blame the Iranians for building one - they look around and see that , when push comes to shove, you can be left very much on your own in this tough world. Compare N Korea & Libya.............
And Pakistan wouldn't last long if India decided to get tough -so they built a bomb