One of the reason we’re mired in forever wars is, of course, our ability to print money seemingly ad infinitum. This is an illusion, of course, but it serves as an excuse.

Another, perhaps more important, reason is that we seem to have lost any objective standard for what constitutes “victory” in a military conflict. Did the “War on Terror” eliminate terrorism? No. Did it at least eliminate the terror groups it targeted (al-Qaeda, the Taliban)? Also no. The former morphed into an even worse terror organization (ISIS), while the latter just took over the country we occupied for 20 years to … prevent its takeover of that country.

If war is politics by other means, its objective is to impose political solutions by force that are not diplomatically acceptable to one or more parties. But a peace based on force is fragile and generally ends the moment the superior force is no longer there to impose it.

This is why a rules-based international order matters. The only way to prevent both terrorism and constant war is for participants in the order to feel like generally everyone is more or less playing by the same rules. Whenever certain players feel like their interests are structurally disregarded, that they cannot achieve meaningful improvements to their status by playing the game of diplomacy, they will resort to violence—either the large-scale, centralized violence of war, or the small-scale, decentralized violence of terrorism.