If there is a war, it is best for us to stay out of it. If Russia wants to get involved so be it, let them lose millions of troops. Israel will always be protected by God with or without us.
However, it is hard to stay out of a war when our bases in the Middle East and in Isreal have been hit hard ... by Iranian missiles and Syrian chem weapons. Russia is on the Arab/muslim side; they will lose no troops to the Arabs, since the Russians are their largest supplier of weapons, outside of Iran.
Not to mention our naval ship losses and sailors in the thousands. There is as yet no proven deterrent to Iranian small boat swarm tactics, and the latest naval incident - Aegis Class destroyer being rammed by a tanker - does not inspire confidence in our navy's commanders in the Gulf.