The US State Department on Thursday gave the green light for the sale of a cutting-edge medium-range missile defence system to its Gulf ally Kuwait. The $3 billion purchase will allow Kuwait to own the National Advanced Surface-to-Air Missile System, known as NASAMS, used by Washington to protect the airspace above the White House and the Pentagon. This approval comes after the US approved the potential sale of operational and training rounds for M1A2 Abrams tanks to Kuwait last month, in a deal valued at up to $250 million. The equipment would provide Kuwait with the ability to deter and defe…