Final answer:
General Sir Henry Clinton replaced General William Howe and led the British Southern Campaign during the American Revolutionary War, which initially saw success but eventually contributed to British defeat.
Step-by-step explanation:
General William Howe was replaced by General Sir Henry Clinton, who was in charge of Britain’s Southern Campaign during the American Revolutionary War. After General Howe's tenure characterized by actions such as the peace conference of September 1776 and military operations like the Battle of Long Island, the British shifted their focus to the Southern colonies due to a stalemate in the war by 1778. This new strategy initially brought success to the British under the leadership of General Clinton, capturing areas such as Savannah and gaining support from Loyalists, Native Americans, and enslaved Africans. However, the American Revolution turned in favor of the Americans, especially with figures like General Nathanael Greene adopting tactics that ultimately led to American victories at battles like Cowpens and Guilford Courthouse, contributing to the eventual British defeat.