How did L'Ouverture's revolution (in Haiti/Saint Domingue) benefit the United States?

The Louisiana Purchase would never have happened without it. You see, before Napoleon sent his 30,000 troops to Saint-Domingue in 1802, he had engaged in a secret series of negotiations with Spain to return the Louisiana Territory to France. The deal, which was completed in 1800, brought Louisiana under French control for the first time since 1763.