The last "Israeli spy" I remember hearing about was actually someone who volunteered to spy for the Israeli's. The Israeli's made agreeable sounds and then called the US State department or whoever to notify them that they had been approached by so-and-so who was offering to spy for them.
Some Russians were caught who were acting as couriers for real spies here in the USA. And there was some acknowledgement from the NSA awhile back that they knew or assumed they had at least one Russian spy on the inside that they couldn't identify. And there was a Chinese industrial spy caught some time ago.
I wouldn't say that we're catching ally spies all the time. Periodically catching spies, of any alignment, might be more accurate.