And an infrastructure that will aggressively support the new government has been established in the countryside. No hard and fast rule can be set that we never stay longer, because every situation is different. But two powerful objections must be posed to any extension. The first is the probable political situation at home. If any administration that approves an intervention ends up paying for it with its political life, we will very seldom intervene anywhere, regardless of what interests we have at stake.
Politicians are quick learners where holding onto office is concerned.
Prolonged interventions, with the steady dribble of casualties they invariably involve, have very high political costs. The second objection relates to the country where we have intervened. We live in a world in which the nationalism that arose in Europe in response to the French Revolution has spread almost universally. Any foreign presence rubs this nationalism the wrong way. The longer we stay, the more we assist our opponents in preaching the case for a national war.