Not content to simply insist that a ship at sea answered to no authority at all, Jefferson Davis stepped up his defense of William Walker by playing dumb:
I think we should execute our neutrality law within our own limits; but I hold that the difficulty which has so often occurred, and which has so often permitted expeditions of this kind to leave the United States, is inherent in the nature of the case. Our neighbors are too weak to require that a regular armament should be fitted out, that an army should be organized for their invasion. It is not according to the theory of our government that we should establish a system of espionage in order that we may stop any six, twenty, one hundred, or two hundred men who may choose to leave the United States, cast off their obligations to our Government, and enter into revolutionary movements elsewhere. If they claim to be emigrants, what right have we to inquire into their future motives?
Davis said that bit about a system of espionage to stop people from leaving of their own free will whilst supporting a de facto system to do just that, so long as someone owned the emigrants in question. But slaves did not count and the spectacle of armed black men would probably have provoked a white mob in most any state of the Union at the time.
But on the subject of filibustering Davis insisted that we just don’t know what Walker and his men meant to do. Nevermind that they had fundraisers and Walker openly, even then and even in Washington itself, declared his intentions. But even if we did know, Davis maintained:
They are not, in the sense in which the term was used in 1818, a military expedition, but a mere handful of adventurers upon a transport-boat going down to a landing on the coast of Central America. Such an expedition as need be fitted out to go into the harbor of Liverpool, and there make an assault, could not leave our coast without every man in the country knowing it. Such an expedition it would be perfectly within the power of the United States to suppress. But, sir, when my attention was directed to this subject some years ago, at the time of the invasion of Lower California, when we received intelligence of a handful of men, (I believe it was but a dozen,) with side-arms, going and capturing the Governor and proclaiming themselves conquerors of a State, I felt out utterly idle it was for this government, with our right of expatriation, with the right of each and every citizen to go where he pleases, and to bear arms, to attempt to suppress such expeditions as might be of use against the southern and Central American states.
Walker’s expedition did not fall under the terms of the act. He and his men just happened to emigrate with guns on hand and what they did beyond the shores of the United States didn’t matter. Even if it did, the United States had no power there. True enough, so far as it goes. The United States would not get very far trying to enforce its laws on British territory. The entire international order from the end of the Thirty Years’ War onward rested on national sovereignty, which would prevent that kind of action had the Nicaraguans chosen to exercise it. Instead, they chose to exercise their sovereignty by inviting American protection.
Setting that aside, Davis apparently thought it would take thousands of men, at least, to trigger the Neutrality Act, despite that act not putting any minimum size on the expeditions it covered. Who knew? Most military formations in the Civil War era United States amounted to a company or smaller. On paper that meant around a hundred men. Davis effectively claimed that expeditions with more men than most frontier military posts do not amount to a military force. One wonders, then, just who defended the frontier. Private citizens who accidentally dressed similarly?