The Quasi-War was an undeclared war fought almost entirely at sea between the United States and France from 1798 to 1800. After the toppling of the French crown during the French Revolutionary Wars, the United States refused to continue repaying its debt to France on the grounds that it had been owed to a previous regime. French outrage led to a series of attacks on U.S. shipping, ultimately leading to retaliation from the U.S.
The war was called "quasi" because it was undeclared. It involved two years of hostilities at sea, in which both navies attacked the other's shipping in the West Indies. The unexpected fighting ability of the U.S. Navy, which destroyed the French West Indian trade, together with the growing weaknesses and final overthrow of the ruling Directory in France, led Talleyrand to reopen negotiations. At the same time, President Adamsfeuded with Hamilton over control of the Adams administration. Adams took sudden and unexpected action, rejecting the anti-French hawks in his own party and offering peace to France. In 1800 he sent William Vans Murray to France to negotiate peace; the Federalists cried betrayal. Hostilities ended with the signing of the Convention of 1800. [See Wiki HERE]