D’Estaing’s arrival inspired Washington’s second Westchester deployment. The American commander stationed the Continental Army in White Plains, and from his headquarters at the Purdy House laid plans with d’Estaing for a joint naval and land assault against British-controlled Manhattan. (The Jacob Purdy House is preserved in a serene setting at 60 Park Avenue.)
But the plan went nowhere. To Washington’s intense frustration, the naval effort against New York was a
non-starter: The deep draft of the
French ships prevented them from cro-
ssing the shallow waters at Sandy Hook and entering New York Harbor. Absent the French fleet, Washington could not, on his own, risk a move from Westchester against the formidable British defenses on Manhattan, and he withdrew into
the Hudson Highlands.
The non-starter at New York Harbor, which was followed by further disappointments involving d’Estaing’s fleet, convinced France to reassess its strategy and make a much stronger commitment to the American rebellion. Accordingly, King Louis XVI of France asked a battle-tested general, the comte de Rochambeau, to assemble an expeditionary army of 5,000 troops for service in America and instructed Rochambeau to place himself, when he arrived in America, under the command of Washington.
Rochambeau’s army left France in May, 1780, intending to disembark at Newport, Rhode Island, in July. This timing, as it turned out, was perfect for General Benedict Arnold, who had been making treasonous overtures to the British for more than a year.