Senator Obama is viewed by Israelis as having less commitment to their security than do either President Bush or Senator McCain. The accuracy of this perception is not particularly relevant, note merely that the Palestinians believe it too. In emotional issues like national security, perception often trumps reality.
If Obama is elected our next President in early November, the two month period between the election and Inauguration Day in January, 2009, features a greatly increased likelihood of Israeli attack on Iranian nuclear facilities. The logical time for Israel to attack Iran's nukes is before Obama occupies the White House; while Israel can still count on at least tacit support for such raids.
On the other hand, if McCain is elected Israel will feel less pressure to act immediately against Iran. I believe the consensus will be that they have more time to assess the situation and weigh their options. In this sense, a win by Obama increases the temporal predictability of future events, if not the likelihood of their occurrence.
