The Continental Army drove the British soldiers out of Boston in March 1776, but that same summer and until the end of the war lost New York and its strategically important harbor. The Royal Navy occupied the ports and captured the cities for a short time, but they were not able to defeat the army of Washington. In the winter of 1775 - 1776, militias tried to invade Canada to subjugate the British province of Quebec, as well as to join the French Canadians to participate in the war on the side of thirteen colonies. The campaign was unsuccessful, but in October 1777, the Americans won the battle of Saratoga. France entered the war as an ally of the United States, with a large army and navy. Then the military operations were transferred to the territory of the southern states, where Charles Cornwallis in 1780 successfully captured the British army in Charleston, South Carolina; he fails to attract enough volunteers from among the loyalist residents to effectively control the territory. Finally, in the fall of 1781, the combined American and French forces captured the 2nd British Army in Yorktown, thereby putting an end to the war.
Germany's resumption of submarine attacks on passenger and merchant ships in 1917 became the primary motivation behind Wilson's decision to lead the United States into World War I.
