  David Estlund has tentatively advanced a new and intriguing suggestion for shoring up an essentially voluntarist account of authority. Estlund argues that even in the absence of explicit or tacit consent in some cases persons may be said to have consented to political authority.  He describes this as “normative consent”.  The idea is motivated in the following way.  Estlund notes that actual explicit cases of consenting can fail to produce obligations if what is consented to is seriously immoral.  The consent is nullified (in its obligation producing effect) by the evident immorality of its content.  Estlund then enquires as to whether the lack of consent under certain circumstances mightn't similarly be nullified in cases where it is plainly wrong not to consent.  Why aren't these symmetrical he asks?  Estlund envisions a case in which a passenger airplane has crashed and in which there is still a significant chance of saving many passengers through a very well coordinated effort.  As it happens an airline attendant stands up and “takes control” by giving commands to various people thus organizing the relief effort.  Let us suppose that this is evidently reasonably successful but that it really does require the cooperation of (nearly) everyone to whom the airline attendant chooses to give directives. And let us suppose that the attendant is not giving any clearly immoral commands.  Estlund notes that it would be clearly immoral for someone in a position to give essential help not to agree to go along with the attendant's commands.  Now suppose that someone in such a situation refuses to consent to the arrangement.  Estlund asks whether their non-consent isn't nullified in the light of the fact that it is immoral not to consent.  And if the non-consent is nullified, then its normal effect in preserving the liberty of the agent is not produced.  In this case the person is no longer free to act independent of the purported authority.  Since his non-consent is nullified, he has, in effect, consented and he is therefore under an obligation to the authority.  This is normative consent.