  One suggestion holds that it is the wrongness of the act threatened that makes the use of such a threat a wrongful act itself. Mitchell Berman has argued that when a coercer threatens to do something, the rightness or wrongness of the use of such a threat to coerce depends on whether it would be rightful or wrongful for that agent to carry through with that threat (Berman 2002). Berman's account of wrongful coercion thus apparently relies on a principle of inference that holds that if it is wrong to do A, then it is wrong to threaten to do A, and vice versa. While this principle would seem to get support from a lot of particular cases, it's not clear that it holds in all cases. At least sometimes it appears appropriate to threaten to do something which would be wrong to carry out (nuclear deterrence is sometimes thought to be like this; see Section 4.1 below). And sometimes it may be wrongful to threaten what it would be right to carry out (blackmail and extortion are sometimes thought to include such cases). In general, making a conditional threat allows for considerable ethical complexity because a threat can amount to nothing more than a bit of communication, yet in some circumstances such communication is tantamount to an act of considerable violence, with similar consequences. In fact, making a conditional threat is often a more troublesome and ethically problematic act than making a plain, unconditional  threat.[20]  Unfortunately, the ethical complexities involved in the making of conditional threats have been little explored to date by those more centrally interested in  coercion.[21]  (For criticism of and an alternative to Berman's approach, see Anderson 2011.)