In 1967 Israel attacked the USS Liberty.
http://www.lewrockwell.com/orig/margolis12.html
There is disagreement on whether Israel knew it was a US ship. Some say they knew, others say they of course, did not.
They address that claim. If I remember correctly that the Soviets test flew the prototype (which was available though yet unknown to NATO at the time)and they have apparently admitted to doing so. Also, the flight envelope of the reconnaissance aircrafts that overflew Dimona was just not possible to achieve with any other type than in service.
Anyway, the main idea is that the ruskies where serious about using a nuclear strike or a landing in Israel (in conjunction with the main Arab thrust) to prevent it from acquiring nukes, and that only the swift victory over the Arabs made any soviet intervention wholly pointless. If we switch Israel with Iran and the USSR with the USA that books almost reads like 2011.