But he said: "I think there is a large dose of wishful thinking here.
"I can just as easily give you a scenario whereby exactly the opposite will happen -- that as a result of the U.S. implanting itself in the heartland of the Arab world, there will be an acute reaction and there will be more extremism and more incitement against the United States."
Yaalon, who has served as military intelligence chief, said in a newspaper interview a week ago that "a U.S. attack in Iraq will trigger a regional earthquake" in the Middle East.
"After it, I believe there will be a new balance in the region, a new structure. A successful American offensive will...strengthen all of the pragmatic parties in the region."
But commentator Yigal Sarna, writing in the Yedioth Ahronoth newspaper, said it was all "security spin" aimed at hiding what he called Sharon's failure to deliver on promises of peace during a now 28-month-old Palestinian uprising for statehood.
"After Saddam and Abu Ammar (Arafat's nom de guerre) are gone, the world will be a wonderful place, just like the fairy tale in which the wicked witch is dead," he wrote sarcastically.
"But Israelis are asking themselves what will really change -- and they know: nothing."