The true statement concerning the campaign of the summer of 1778 is:
General Howe was replaced by General Clinton to command the British Army.
In 1778, General William Howe was replaced by General Henry Clinton as the commander of British forces in America. The other statements are not accurate. The Battle of Monmouth was not a decisive victory for either side but was a significant engagement for the Continental Army. Washington did not stay at Valley Forge during the summer of 1778; he was actively engaged in military operations. Additionally, many Indigenous peoples were involved in the conflict, often aligning with the British.