I don't know about the US spying on Israel, but Israel and the UAE actively spy on the US, and this arrangement is pretty much allowed. I do know that US embassies in both places "monitor" their host countries, which is significantly different from spying and intercepting comms.
Interesting that the US doesn't actively spy on its partners, at least in their home countries, yet they allow it to be done to them. I don't follow this stuff closely so I can't really contribute. I'm sure others here would like to hear more.
I do remember when Israel's cell tower interceptors were found in D.C.
It probably has something to do with Israel being very popular with wide swaths of the American public (particularly evangelical Christians), to such an extent that it's not terribly uncommon to hear American politicians praise Israel to garner more support from themselves.
Israel gladly accepts all the help it can from the US, but is well aware of the large support that American anti-zionist and pro-palestinian causes receive. They also don't trust certain administrations to always have their back, even if stated publicly.
In summary, Israel always has a bunker mentality of "us vs. the world". The US, while an ally, isn't immune from suspicion and active and aggressive spying efforts.
I mean, perhaps not on the ground in Israel (which amounts to a small technicality). They still keep tabs on Israel activity everywhere else.
Allies in general don't mind being spied on, as long as that intel is shared. For example, German security forces had no idea about the Hamburg cell plotting 9/11 in their country. They would very much wanted a tip off, even from an allied spy agency.
You are correct regarding SIGINT, that allies don't mind being spied upon. What they do mind is when they themselves are being spied upon. Like Merkel's phone being tapped. Or the US recruiting on ground assets in Saudi Arabia.
> What they do mind is when they themselves are being spied upon
That's what SIGINT is.
> Like Merkel's phone being tapped.
Which is an example of SIGINT. And it was leaked which is why it became an issue. World leader's are always surveilled.
There's a certain level of aggression you use against acknowledged enemies that would be awkward if exposed against allies, that is not to say it doesn't still happen.
Oh, my bad at that, got a brain fart I suppose. Sweeped surveillance (which is usually SIGINT) is not minded, and often the backbone of programmes such as Five Eyes relies on that. Targeted surveillance (SIGINT cases that I mentioned) and espionage (mostly HUMINT) is frowned upon. HUMINT is especially frowned upon since it means you're actively investing in recruiting citizens against their government, and the intel is usually much more valuable and more expensive to garner. HUMINT Intel isn't practiced between staunch allies either, but maybe between uneasy allies and enemies.
