I found the quote quoted as follows:
"Government," he has told us, "has three primary functions: It should 
provide for the military defense of the nation. It should enforce contracts 
between individuals. And it should protect citizens against crimes against 
themselves or their property." Milton, I'm relieved Defense made the cut. 
(laughter)

Secretary of Defense Donald H. Rumsfeld
Tribute to Milton Friedman
White House, Washington, D.C., May 9, 2002

I also saw the quote appearing without quotation marks in a free term paper 
website.

Nicholas J. Theocarakis