On October 10 and 12 of this year, we speculated that an Obama victory on Nov. 4 would raise the likelihood of an Israeli strike on Iran in the immediate post-election period. Ceterus paribus, that would still be the case. [Ceteris paribus is Latin meaning "all other things being equal," a usage much beloved by academics.]
However, it turns out that in recent Israeli domestic politics, ceteris is definitely not paribus. As this New York Times article notes, the present Prime Minister, Olmert, has resigned over ethics issues and Livni, the woman who replaced him as leader of the Kadima party, has been unable to assemble a new governing coalition.
Early elections have been called to happen in February or March, 2009. The article speculates that Olmert will probably continue as acting Prime Minister until the elections. What all this means is that Israel will have a weak government between now and the inauguration of a new U.S. president in late January.
Lame duck governments tend not to launch military strikes as such governments are perceived to have little public support. So...an Obama victory in November may not increase the immediate likelihood of an Israeli strike on Iran. In this case Israeli domestic politics probably trump their foreign policy concerns.
