Clue: Poor Joe B getting totally disheartened? Admiration often expressed for his opponent (2,5,1,5,3)
Answer: I’M DOING A GREAT JOB
Explanation: Definition: often expressed for his opponent
Anagram of JOE B G[ettin]G ADMIRATION. Often expressed *by* his opponent, surely, though of course, as in most cases, it's about himself. This was almost my last one in, perhaps because there's such a large collection of idiotic Trumpisms to choose from