In its reaction on the terroristic attacks of September 9th, 2001, the US-government threatened Afghanistan's Taleban with war in order to force them to extradite terrorist leader Bin Laden; the Taleban said that they would not surrender to this kind of blackmail – and so, they were removed from Kabul by means of military force. The rivalling versions of this story depend crucially on notions such as "terrorism" and "blackmail". Obviously you'll gain public support for your preferrend version of the (...) story if you are able to determine how those notions are to be used. So we had better reflect about their very meaning and about the moral implications of their proper usage. To gain a deeper understanding of our notions of "blackmail" and "terrorism" I shall propose an extreme thought experiment: Cassandra's plan. Cassandra foresees that sooner or later one of the nuclear powers might take the liberty to use atomic bombs. From fright she founds an NGO for blackmailing the statesmen who are in charge of nuclear weapons; she announces in public that all ministers and leaders of any government shall be hunted down, and executed, whose soldiers drop but one atomic bomb. (Cassandra's NGO keeps killer teams in constant training so as to increase the effect of the threat; this is being financiated from private donations). In my paper I shall raise two questions (without claiming to provide definite answers). First, would we have to say that Cassandra's NGO was a terrorist organisation? Second, would it be morally wrong if Cassandra blackmailed statesmen in the way indicated? (shrink)