When did the governors of states authorize to fly the US flag at half mast?

1SG Scott MacGregor, I think the USC states, "In the event of the death of a present or former official of the government of any State, territory, or possession of the United States, the Governor of that state, territory, or possession may proclaim that the National flag shall be flown at half-staff."

In NY Recently The Gov. Of NY ordered the following

Governor Andrew M. Cuomo today ordered flags on all state government buildings to be flown at half-staff in memory of New York City police officer Brian Moore, who died yesterday. Flags will be flown at half-staff beginning today, and remain at that position until Officer Moore’s interment. Officer Moore was shot while on duty over the weekend in Queens.

“Officer Moore put his life on the line in order to protect his fellow New Yorkers, and our state is a better place because of him,” Governor Cuomo said. “Like so many of his brothers and sisters in uniform, Officer Moore served with selflessness and courage, and he will be greatly missed. Our thoughts and prayers are with his family.”

Effective: Tuesday, May 5, 2015


http://www.ushistory.org/betsy/faq.htm