After having been forecast for nearly four years, observers are again arguing that an Israeli or American strike on Iran may occur. The logical question many have regarding this possibility is how such a strike could occur given that the punch has been telegraphed for so long. Isn't three years enough warning to make an attack operationally impossible? History suggests that an attack would still be possible to mount with the element of surprise.
Frist, it is worth going over the literature on surprise in war. Most are familiar with Cynthia Grabo, Efraim Karsh, and Richard Betts' texts. But perhaps the most cogent comment comes from Robert Leonhard, normally a theorist on operational warfare. Surprise, Leonhard argued, is merely the delayed recognition of attack. The aim of surprise is simply to slow down a reaction to an attack as much as possible. Leonhard and William McRaven both observe that it is simply impossible for defenses to stay on full alert all the time, with no weaknesses in any sector of the defense. The aim of early warning systems and intelligence is to give sufficient warning of a strike to blunt the attack's impact at the point of the spear.
In 1941's Pearl Harbor attack and 1944's Normandy landing, the defenders both had an idea that either an attack was inevitable or at least highly likely. It is difficult to conceal large-scale mobilization or preparation for a strike, especially in an atmosphere of diplomatic tension. But sorting through the "noise" of rumor, misdirection, and deception is equally difficult, especially when defending hinges on learning the time, place, and method of attack. McRaven also notes that special operations attacks have succeeded even when the attacker understands the place and method of attack (and even a rough estimate of the time), due to the problem of maintaining constant readiness.
The 1973 Yom Kippur attack is probably the most relevant case study. The Israelis had endured years of low-level warfare with Egypt and Syria since 1967 and witnessed constant Egyptian saber-rattling and mobilization. Although the causes of the intelligence failure are complex, one major contributing factor was the fact that the Israelis had been dulled into complacency by the false alarms. They also mirror-imaged the Egyptians, thinking that the Egyptians would wait until they had developed the ability to contest Israeli airspace to launch an attack.
A prospective Iranian decisionmaker examining the constant false alarms, the relative strategic and cost and benefit of a strike, and adversary domestic politics could thus make an "israeli" mistake. Such an error, in turn, would enable a strike to occur with the element of surprise. How that surprise is employed, and whether or not the attack would be successful in accomplishing strategic aims is another matter entirely. But surprise is possible.