1. A French-controlled Louisiana would threaten American trade and commerce: American leaders feared that France would use its control over Louisiana to limit American access to the Mississippi River and the Gulf of Mexico. This would have had a devastating impact on the American economy, which was heavily reliant on trade.
2. A French-controlled Louisiana would be a base for attacks on the United States: American leaders also feared that France would use Louisiana as a base to launch attacks on the United States. This was a particular concern because France was a powerful military power with a large navy.