The "standing army" of the 18th century was of concern, because its primary function was domestic enforcement of the will of the government. One of the major "checks and balances" they installed, was to try to ensure that the federal government would have NO ABILITY to enforce its decrees without the active support of local authorities.
In 21st Century America, armed "federal law enforcement" is the standing army the Founders so feared.
This, and rightly so !
Our Armed Forces are by and large patriots, but those maggots are the true 'jackbooted thugs'.
See: Waco, Ruby Ridge, et al.