It is natural for Romney to go to Israel. He has been friends with Prime Minister Netanyahu for 36 years. Although Netanyahu is nominally impartial in American elections, he has close ties to Republicans, and a frosty relationship with the incumbent. President Obama will surely carry a majority of the Jewish vote in November, but if Romney can just slightly improve the GOP percentage in this segment of the electorate, he might have a better chance of carrying Florida.
The trip to Poland has electoral significance. There are large clusters of Polish Americans in Michigan and Pennsylvania, two large states that Romney might be able to carry in November.