<P> Public opinion in France was in favor of open war, but King Louis and his advisors were reluctant due to the possible risks and heavy expenses involved . The king's economic and military advisors, in particular, remained reluctant . The French Navy was being rapidly rebuilt, but there were doubts as to how ready it was for serious conflict . Financiers Turgot and Necker warned war would be very expensive for France's wobbly system of taxation and finance . </P> <P> The Americans argued that an alliance of the United States, France, and Spain would assure a rapid defeat of the British, but Vergennes, waiting until his navy was ready, hesitated . On July 23, 1777, Vergennes decided that it was time to decide either total assistance, with war, or abandonment of the new nation . The choice, ratified by the king, was war . </P> <P> The British had taken Philadelphia in 1777, but American victory at the Battle of Saratoga brought back hope to the Patriots and enthusiasm in France . The army of Burgoyne surrendered to American forces after Saratoga and France realized that the United States could be victorious . The king directed Vergennes to negotiate an alliance with the Americans . </P> <P> France formally recognized the United States on February 6, 1778, with the signing of the Treaty of Alliance . Hostilities soon followed after Britain declared war on France on March 17, 1778 . The British naval force, then the largest fleet afloat, and French fleet confronted each other from the beginning . The British avoided intercepting a French fleet that left Toulon under the comte d'Estaing in April for North America, fearing the French fleet at Brest might then be used to launch an invasion of Britain . France had kept the Brest fleet to protect commercial shipping in European waters, and it sailed out only after a British fleet was confirmed to have left in pursuit of d'Estaing, thus weakening the British Channel fleet . In spite of this reduction, the British fleet still outnumbered the French fleet at Brest, and Admiral d'Orvilliers was instructed to avoid combat when he sailed in July . D'Orvilliers met the fleet of Admiral Augustus Keppel in the indecisive Battle of Ushant on July 27, after which both fleets returned to port for repairs . </P>

When did the french become allies with america