"National Guard of the United States" became a standard nationwide militia title in 1903.
 The Militia Clauses gave Congress authority for "organizing, arming, and disciplining" the militia, and "governing such Part of them as may be employed in the Service of the United States", and the States retained authority to appoint officers and to impose the training specified by Congress
Beginning in the late 20th century, some militias (in particular officially recognized and sanctioned militias of a government) act as professional forces, while still being "part-time" or "on-call" organizations

