In 1795, Spain granted Western farmers the right to ship produce down the Mississippi River to New Orleans, where their cargoes of corn, whiskey, and pork were loaded aboard ships bound for the east coast and foreign ports. In 1800, Spain secretly ceded Louisiana Territory to France, and closed the port of New Orleans to American farmers. Westerners, left without a port from which to export their goods, exploded with anger. Many demanded war.
The prospect of French control of the Mississippi alarmed Jefferson. Spain held only a weak and tenuous grip on the river, but France was a much stronger power. Jefferson feared the establishment of a French colonial empire in North America blocking American expansion. The United States appeared to have only two options: diplomacy or war. In response to growing concerns from the western states, Jefferson, with Congressional approval, called for the state governors to raise a militia of 80,000 men in preparation for a possible war with France.
...I take the liberty of urging on you the importance and indispensable necessity of vigorous exertions, on the part of the State Governments, to carry into effect the militia System adopted by the national legislature, agreeably to the power reserved to the states respectively by the constitution of the United States, and in a manner the best calculated to ensure such a degree of military discipline and knowledge of tactics, as will, under the auspices of a benign providence, render the militia a sure and permanent bulwark of national defence.
None but an armed nation can dispense with a standing army. To keep ours armed & disciplined, is, therefore, at all times, important, but especially so at a moment when rights the most essential to our welfare have been violated, and an infraction of treaty committed without colour or pretext.... While, therefore, we are endeavoring, of with a considerable degree of confidence, to obtain, by friendly negotiation, a peaceable redress of the injury and effectual provision against its repetition, let us arrange the Strength of the nation, and be ready to do with promptitude and effect whatever a regard to justice and our future security may require.