The story
First appears c. 1980 in the US. Attributed to the United States General Volney F. Warner, as quoted in the Christian Science Monitor (April 11, 1980) in reference to the Iranian hostage crisis
Etymology from Wiktionary, CC BY-SA 4.0.
boots on the ground
Today it means: The ground forces actually fighting in a war or conflict, rather than troops not engaged or other military action such as air strikes. Full definition →