NASHVILLE (January 24, 2013)--Lee Greenwood is marking the 30th anniversary of "God Bless The U.S.A.," which he wrote in 1983 in response to an incident in which Russian authorities mistook a Korean jet on its way from New York to Seoul for a spy plane and shot it down with 269 passengers on board.

Since then, it's become an anthem during the Gulf War, after 9/11, during the Iraq War and after Hurricane Katrina.

Greenwood says the song came so easily, it nearly wrote itself.