Historically, new wars help the incumbent.
I don't see Israel as eager to help Obama.
However, they may believe Rmoney is a better ally but don't want to gamble him not being elected.
If Rmoney loses then Obama has no motive to assist/not-hinder Israel.
Attacking just before the election forces Obama to pick a side.
Either Israel gets its needed or aid the US gets a new president.
A short term vs long term boon for Israel.