Filibustering (Freehling, 2007)

The qualms about the Caribbean (and about New Orleans) fed qualms about the illegality of filibustering. Before U.S. filibusterers could replace foreign regimes, they had to defy their own national’s Neutrality Laws. Back when the new American government had striven to be neutral in Europe’s Napoleonic Wars, Congress had passed these laws. These edicts required private individuals to be as neutral as their government. American citizens could not join foreign wars, civil conflicts, or revolutions when the United States remained at peace with the combatants. . Federal officials could seize suspected filibusters before they sailed from America. If convicted, suspects could be fined up to $3000 and jailed for up to three years.

In the presecession years, the northern presidents who presided over national laws enforced these edicts enthusiastically. Both Pierce and Buchanan sought legal purchases in the Caribbean as zealously as they repressed illegal freebooting from the United States. That even-handed attitude toward expansionism, they believed, best ensured sectional peace. Intolerance for lawbreakers also best preserved a nation worth saving.