Why will USA hit Russia? Russia in this scenario won't be nuking USA it will be nuking Mecca... why would USA put its own existence on the line just because KSA has been destroyed.... strike on Russia will trigger Russia's 2nd strike SSBNs heavy SLBM and SLCM heavy Mirv each missile with 8-12 warheads... USA will also be destroyed if it messes with a NUCLEAR SUPERPOWER!! Only 2 Nuclear Superpowers in the world Russia and USA...
Truth be told Iran needs the best deterrent a country can have which is SSBN on board with ICBM SLBM Mirved...