Was this example really necessary? You basically said: If terrorists (who, by the way, happened to travel to Afghanistan once) attacked the WTC, the US have a c

Was this example really necessary? You basically said: If terrorists (who, by the way, happened to travel to Afghanistan once) attacked the WTC, the US have a casus belli against Afghanistan. See, the reason why the war in Afghanistan is controversial is precisely because it is not clear that a country has a casus belli against another country if there is a (remote) connection of offenders to that country. In fact, the pilots lived and planned most of the plot in Germany. A better example of a failed state would be the results of the war on drugs in Mexico.