As part of the expanded trade between Great Britain and the US as a result of the Jay Treaties, US merchant ships plied the North Atlantic trade between the countries. The French were unhappy at this and, despite a treaty relationship with the newly-formed USA, began attacking the unarmed and unescorted merchantmen. At that time the US have virtually no naval force. The French seized nearly three hundred American ships bound for British ports in the Atlantic Ocean and Mediterranean and Caribbean Seas. Federalist leaders such as Alexander Hamilton called for war, but President Adams sent a diplomatic delegation to Paris in 1797 to negotiate peace. Three French government agents, Jean Conrad Hottinguer, Pierre Bellamy, and Lucien Hauteval, demanded a large cash bribe for the delegation to speak to the French foreign minister Charles Maurice de Talleyrand-Périgord; a huge loan to help fund the French wars as a condition for continuing negotiations; and a formal apology for comments made by Adams. The Americans broke off negotiations and went home. Thomas Jefferson's Democratic-Republican Party, fearing that the American delegates were to blame for the failure, demanded to see the key documents. Adams released the delegation's report—with the names of the French agents changed to X, Y, and Z, hence the popular name of both the affair and the correspondence—setting off a firestorm of anti-French sentiment as Americans blamed the French.

  It was seen as unconscionable that France should refuse to negotiate with the accredited U.S. representatives, or even to receive them, without demanding bribes for its leading members and a loan for that nation's military incursions in Europe. This was an extreme insult to Americans. The public learned that the American delegates had rejected the demands. "The answer is no! No, not a sixpence!" was their response (translated by newspaper editors as "Millions for defenc e, but not one cent for tribute!").

  The Quasi-War erupted (1798-1800), with American and French warships and merchants ships fighting in actual combat in the Caribbean and off the east American coast. (It was called "quasi" because there was no formal war declaration.) The Americans abrogated the Franco-American Alliance. Adams began to build up the navy, and a new army was raised. Fortunately, the French were grossly incompetent on the seas.

  At that time the US barely had a navy; less than thirty ships. Fortunately against the French that was enough. On July 7, 1798, Congress rescinded all treaties with France and the US Navy was ordered to seek out and destroy French warships and privateers operating against American commerce. Consisting of approximately thirty ships, the US Navy began patrols along the southern coast and throughout the Caribbean. Success came quickly, with USS Delaware capturing the privateer La Croyable off New Jersey on July 7.

As over 300 American merchantmen had been captured by the French in the previous two years, the US Navy protected convoys and searched for the French. Over the next two years, American vessels posted an incredible record against enemy privateers and warships. During the conflict USS Enterprise captured eight privateers and liberated eleven American merchant ships, while USS Experiment had similar success. On May 11, 1800, Commodore Silas Talbot, aboard USS Constitution, ordered his men to cut out a privateer from Puerto Plata. Led by Lt. Isaac Hull, the sailors took the ship and spiked the guns in the fort.

  On February 2, 1800, Thomas Truxtun, commanding the 38-gun U.S. frigate USS Constellation, was in the Caribbean when he spotted the French 52-gun La Vengeance, commanded by Captain Citizen Pitot, headed to France from Guadeloupe.

Although Truxtun realized his opponent outgunned him, he was convinced that the Constellation's greater manoeuvrability and more accurate gunnery would win the day. A four-hour battle ensued. Again, the French focused their fire on the American rigging, while the Yankee ship pounded away at the Frenchman's hull and timbers. The punishment to La Vengeance was so great that three times the French attempted to haul down their colo u rs. However, in the growing darkness, Truxtun was not able to see the signal of their surrender After five hours of cannon fire, the French managed to weaken the Constellation's mainmast. Truxtun pulled back to repair the damage, and La Vengeance escaped into the darkness.

The Constellation limped to Port Royal, Jamaica, while the French frigate made her way to Dutch Curaçao. In his report to the French government, Pitot reported erroneously that he had just fought an American ship of the line (a class of 74-gun ship that the U.S. Navy didn't have until 1818). The American frigates had become a force to be respected by their opponents.

A year before, in a fight against a more equal vessel, Commodore Truxtun led the Constellation against the 40-gun L'Insurgente. In that battle, on February 9, 1799, Truxtun was headed for the island of Nevis when he caught sight of the French frigate L'Insurgente. After pursuing the Frenchman, Truxtun prepared for action. However, as the two ships were on the verge of engaging one another, a squall engulfed them, snapping the main topmast of the French frigate. The loss of mobility, coupled with the French tendency to fire high into the opponent's rigging, gave Truxtun a deadly advantage.

Unable to manoeuvre and suffering from heavy damage to her hull by American gunnery, the 40-gun L'Insurgente was defeated by the 38-gun Constellation. The battle had lasted only seventy-five minutes. The Constellation suffered three casualties, compared to seventy sustained by L'Insurgente. "A very fine frigate [is] being added to our infant Navy" was the report.

It was the first victory for the U.S. Navy in which an enemy ship was defeated and captured.

During the so-called "Quasi-War," so called because the 'heroic' French refused to make a formal declaration of war and instead just began attacking defenceless U.S. merchant vessels without provocation. The U.S. Navy lost just two naval ships in the war, and recaptured one of those. The French lost 85 naval vessels. On September 30, 1800, the French gave up , signing the Treaty of Mortefontaine and agreeing to return the merchant vessels they had captured.

  Relations with France since then have been marginally better. France  had claimed victory over 2,000 unarmed merchant ships; a traditional French sort of victory against unarmed and unprotected ‘enemies’ like African and Asian colonial subjects or the “Rainbow Warrior”. However, when confronted by an armed and determined enemy, even if that enemy was outgunned, the French chose accommodation and surrender. Not a lot has changed in 300 years.