[Ed. – For starters, it’s not what the founders intended.]
In June 1783, the Confederation Congress was meeting in what is now Independence Hall in Philadelphia. Continental soldiers surrounded the building demanding back pay. They were peaceful, but the intimidation was plain.
Congress asked Pennsylvania authorities to clear away the demonstrators. Pennsylvania authorities refused to do so. Congress accordingly left Philadelphia for Princeton, New Jersey, thereby making that town the national capital for a short time.
This incident confirmed the American Founders in their opinion that the national capital should not be at the mercy of any state. The Founders also knew that in European countries, national office holders could be held hostage by mobs that local authorities were unwilling, or unable, to control.
Securing the national capital from capture was one reason for locating it outside the boundaries of any state. But there were other reasons as well.