Foreign intervention

Main articles: France in the American Revolutionary War and Spain in the American Revolutionary War

From the spring of 1776, France and Spain had informally been involved in the American Revolutionary War, with French admiral Latouche Tréville having provided supplies, ammunition and guns from France to the United States after Thomas Jefferson encouraged a French alliance. Guns such as de Valliere type were used, playing an important role in such battles as the Battle of Saratoga.^[104] After learning of the American victory at Saratoga, the French became concerned that the British would reconcile their differences with the colonists and turn on France.^[105] In particular, King Louis XVI was influenced by alarmist reports suggesting that Britain was preparing to make huge concessions to the colonies and then, allied with them, strike at French and Spanish possessions in the West Indies.^[106] To thwart this, they concluded a Treaty of Alliance with the United States on February 6, 1778, committing the Americans to seek nothing less than absolute independence. Previously France had only been willing to act in conjunction with Spain but now they were willing to go to war alone if necessary. Britain responded by recalling its ambassador, although Franco-British hostilities did not actually break out until June 17, 1778.

French troops storming Redoubt #9 during the Siege of Yorktown

In 1776, the Count of Aranda met in representation of Spain with the first U.S. Commission composed by Benjamin Franklin, Silas Deane, and Arthur Lee.^[107] The Continental Congress had charged the commissioners to travel to Europe and forge alliances with other European powers that could help break the British naval blockade along the North American coast. Aranda invited the commission to his house in Paris, where he was acting as Spanish ambassador and he became an active supporter of the struggle of the fledgling Colonies, recommending an early and open Spanish commitment to the Colonies. However, he was overruled by José Moñino, 1st Count of Floridablanca who opted for a more discreet approach. The Spanish position was later summarized by the Spanish Ambassador to the French Court, Jerónimo Grimaldi, in a letter to Arthur Lee who was in Madrid trying to persuade the Spanish government to declare an open alliance. Grimaldi told Lee that "You have considered your own situation, and not ours. The moment is not yet come for us. The war with Portugal — France being unprepared, and our treasure ships from South America not being arrived — makes it improper for us to declare immediately."^[108] Meanwhile, Grimaldi reassured Lee, stores of clothing and powder were deposited at New Orleans and Havana for the Americans, and further shipments of blankets were being collected at Bilbao.
Spain finally entered the war officially in June 1779, thus implementing the Treaty of Aranjuez. The Spanish government had been providing assistance to the revolutionaries since the very beginning of the war, but it did not recognize the United States officially. The Dutch Republic, which also had assisted the colonists since 1776, declared war on Britain at the end of 1780, and did recognize the United States diplomatically.^[109]