This article has a quote (Dead link) from some gulf cooperation council member about how the US not calling for sanctions on israel, while calling for sanctions on Iraq, North Korea, and Iran was a double standard. He’s at least somewhat mistaken about this…

Israel is one of 3 countries that I know of that did not sign the non-proliferation treaty. The other two both have nuclear weapons, India and Pakistan. It would be a double-standard to hold Israel to a standard that we’re not holding the other two non-signers to. 

The US/UN really can’t sanction those 3 countries for their nuclear programs. They have no legal leg to stand on if they try. The only reason they can with Iran, Iraq, and North Korea is that they all signed a treaty not to do exactly what they are or internally claimed to be doing.