The Quasi-War between the United States and France was an undeclared war and was fought entirely at sea, from 1798 to 1800. Most of the conflicts were in the waters off the South Coastof the USA and the Caribbean Sea.
France had been a major ally of the US in the American Revolutionary War, & had signed in 1778 a Treaty of Alliance with the United States. But in 1794, the American government came to an agreement with the Kingdom of Great Britain, angering France.
The significance of the Quasi War was the debates over
distribution of war powers between the Legislative and Executive
branches of government. The Quasi War took place between 1798 and
1800.