It may be laid down, as a primary position, and the basis...

It may be laid down, as a primary position, and the basis of our system, that every citizen who enjoys the protection of a free government, owes not only a proportion of his property, but even of his personal services to the defence of it, and consequently that the Citizens of America (with a few legal and official exceptions) from 18 to 50 Years of Age should be borne on the Militia Rolls, provided with uniform Arms, and so far accustomed to the use of them, that the Total strength of the Country might be called forth at Short Notice on any very interesting Emergency.

George Washington

"Sentiments on a Peace Establishment" in a letter to Alexander Hamilton (2 May 1783); published in The Writings of George Washington (1938), edited by John C. Fitzpatrick, Vol. 26, p. 289