IIRC, when Napoleon regained Louisiana for the French, he kept it secret for 10 years and didn't reveal that he had obtained it from Spain until turning it over to the US in 1803. If I'm a disgruntled Louisianan settler of any ethnicity, that's a causus belli.
How about this as the POD: from 1776-1789, during the American Revolution (which turns out exactly the same) non-English-speaking anti-establishment types steer away from immigrating to the 13 Colonies b/c of the war and start settling in Louisiana, especially upland in the Ozarks and around St. Louis. B/c, as new colonists they aren't major land owners, and b/c they tend to be Catholic or firebrand protestant, they are very anti-slavery.
Then, in 1796, Haiti rebels, right on time. The colonists find out that they've been sold back to the French. Getting into the general French spirit, they throw a revolution of their own, declaring that, by right of the 1789 Revolution, all people of Louisiana and Haiti have liberty, egalite, fraternite. With the Spanish barred from invading and Napoleon unable to spare the troops, the Louisianans quickly succeed and then fight on the side of the Haitian slaves. The result is a united Republique D'Nouveau Monde (since Louisiana is a monarchist name and Haiti is a local name).
How about this as the POD: from 1776-1789, during the American Revolution (which turns out exactly the same) non-English-speaking anti-establishment types steer away from immigrating to the 13 Colonies b/c of the war and start settling in Louisiana, especially upland in the Ozarks and around St. Louis. B/c, as new colonists they aren't major land owners, and b/c they tend to be Catholic or firebrand protestant, they are very anti-slavery.
Then, in 1796, Haiti rebels, right on time. The colonists find out that they've been sold back to the French. Getting into the general French spirit, they throw a revolution of their own, declaring that, by right of the 1789 Revolution, all people of Louisiana and Haiti have liberty, egalite, fraternite. With the Spanish barred from invading and Napoleon unable to spare the troops, the Louisianans quickly succeed and then fight on the side of the Haitian slaves. The result is a united Republique D'Nouveau Monde (since Louisiana is a monarchist name and Haiti is a local name).