[dumbledoren]

It goes far beyond that: France sent troops and France and Spain sent their navies to protect the East Coast and fought with the British navy to prevent them from landing forces. They also prepared an invasion to invade the British isles, which tied what forces Britain had remaining to the British isles. That is how the small rebel contingents were able to win against the scarce British presence. Even that required Lafayette to come up from the south with his French contingent and do a pincer move.