For leaders, it can be exquisitely complex. Whether out of strong belief, a sense of duty, or another purpose, a leader may work, politic, or fight for a cause some judge reprehensible. But the moral validity of the cause doesn’t determine the success or effectiveness of the leadership. Great leaders can serve bad causes as often as lousy leaders represent the most noble of efforts.
This is an important position. Ever since James MacGregor Burns wrote Leadership in 1978, there has been a school of thought that equated "leadership" with morality. If you weren't working for good, then Burns and others said it wasn't leadership.