 During Cornwallis 's absence , control of the British forces had passed to Henry Clinton on the resignation of General Howe ; as a consequence , Cornwallis was now second in command in North America . After the surrender of John Burgoyne 's army at Saratoga and the entry of France into the war , the British decided to withdraw from Philadelphia to concentrate defenses in New York against the French threat . Cornwallis commanded the rearguard during the overland march from Philadelphia to New York City and played an important role in the Battle of Monmouth on 28 June 1778 . After a surprise attack on the British rearguard , Cornwallis launched a counter @-@ attack which checked the American advance . However , when he then led elite units against an entrenched Continental Army position , it refused to budge , and Cornwallis was forced to withdraw with heavy casualties . Even though Clinton commended Cornwallis for his performance at Monmouth , he eventually came to blame the earl for failing to win the day . 
