The Saudi-Pakistan defense pact could give Riyadh a nuclear-backed deterrent as Iran, Israel and US reshape Gulf security calculations The rapidly evolving security landscape in the Middle East is prompting Saudi Arabia to rethink its national defense strategies. With no reliable guarantees of American protection, Riyadh is looking to establish an alternative framework for reliable defense – and surprisingly, Pakistan is becoming its key component.  The Saudi-Pakistani Strategic Mutual Defense Agreement (SMDA), signed last September by Crown Prince of Saudi Arabia Mohammed bin Salman and Prime Minister of Pakistan Shehbaz Sharif, is one of the most significant pacts between the two nations in recent decades. Its central provision states that aggression against one state will be automatically regarded as aggression against both, echoing the principles of classic collective security treaties and formally establishing allied relations between the two countries.…