I believe that Olmert feels hamstrung by Iranian and Syrian rockets pointed at Dimona and other Israeli nuclear facilities.
I'd hate to think an Israeli leader believes this to be strategic deterrent. One can hardly compare the Syrian/Iranian aresenals equivalent to Israel's 200-400 deliverable nuclear warheads. No doubt an Iranian/Syrian missile barrage would hurt, but losing this war in the long term may hurt worse.
Dioma could potentially be hit by Katusha's from the West Bank (about 19 miles distant), but is about 135 miles south of Lebanon. The farthest the currently known missiles from Hezbollah can go is about 35 miles.