The news of yet another terrorist attack by ISIS on European soil in a few years confirms for Europe what has been a reality for some time now in other parts of the world: Armed groups willing to resort to terrorist tactics are a real and continuous threat for international security.
The historian Plutarch narrates how Cato the Elder, after a lifetime of service to the Roman Republic, spent his last days warning Roman senators about the ongoing threat of Carthage. Although defeated in the Second Punic War, the economic prosperity reached by Carthage in following decades prompted deep concern in Cato, who took it upon himself to close every intervention at the Senate with the call “Besides, I think Carthage must be destroyed” (“Ceterum censeo Carthaginem esse delendam”, or “Carthago delenda est”). At last, at the behest of Cato Rome understood the risk that had been growing overseas and defeated Carthage for good in the Third Punic War.
Cato’s story teaches us two important lessons when dealing with tenacious enemies. First, wherever human communities exist, there will be the potential for internal or external conflict, so simply wishing for problems to fade away or for aggressiveness to appease is naïve and irresponsible. As stated by Machiavelli on The Prince, “He who stalls conflict does so at his own peril”.
But, secondly, the radical Roman response to the Carthage problem, amounting to the annihilation of the population, salting the earth and ultimately not leaving “stone over stone”, is not adequate to address the threat of terrorist groups in the 21st century. For over half a century now some principles of international law have been firmly established, fortunately precluding the application of such a drastic formula again, including the respect for human dignity and human rights, for the laws and uses of war and for peoples’ self-determination.
Yet, all of the above does not mean that States cannot resort to the use of force to fight terrorist groups, exerting their right to self-defense. The doors of the temple of Janus – the Roman god for the beginning and the end of war – which Europeans decided to shut 70 years ago, certainly under the cover provided by the United States, seem to have been suddenly reopened by the attacks of ISIS.
Once European countries realize that they cannot keep on reacting to these attacks solely with police “human hunts”, and start considering the military alternative, they will have to comply with the refined criteria of the Just War tradition, including just cause, necessity, legitimate authority, right intention and proportionality between costs and benefits. This means, in part, that they must try not to provoke a new conflict in the future, by exerting responsibly what is known as jus post bellum. It also means that both European countries and the United States will have to seek the support of other powers to make war on ISIS, so as to prevent the costs from surpassing the benefits therefrom. In this regard, the participation of the renewed power of Russia in this collective undertaking is of the essence.