"Under the Supreme Court’s 1973 Enmons decision, vandalism, assault, even murder by union officials are exempt from federal anti-extortion law. As long as the violence is aimed at obtaining property for which the union can assert a “lawful claim”—for example, wage or benefit increases— the violence is deemed to be in furtherance of “legitimate” union objectives. By the Court’s peculiar logic, such violence does not count as extortion."