There will be no US troops in Syria. If Russia and Iran can supply military aid so can the US. You are very naive if you think that Russia would go to war with the US over Syria. Russia's only interest in this conflict is to be able to protect its Syrian bases on the Mediterrean. They would cut loose from Assad immediately if it appears that he is on the way out.
UN: At least 1,332 Iraqis killed by violence in July (AP)