With d'Estaing back to France, Washington got stuck in New Jersey, while asking for a continuous French naval presence in North American waters. When Lieutenant General Comte de Rochambeau arrived in Newport in July 1780 with an army of 6,000 men, he described the situation: "in any operation, and under all circumstances, a decisive naval superiority is to be considered as a fundamental principle, and the basis upon which every hope of success must ultimately depend".[62] The Dutch were helping the American rebels by selling them guns and gunpowder from their ports in the Caribbean. The British used this as a pretext to declare war on the Netherlands in December 1780.