A war for the maintenance or reestablishment of a buffer state is a peculiar beast. It is not a war of conquest, because direct territorial control would undermine the purpose of the buffer. It is also not a war aiming to inflict a massive defeat on the rival power, due to the recognition that such an outcome would be undesirable and unfeasible (hence, it is better to be separated). The objective is to bring back a zone of separation, lowering the tensions between the rivals and allowing for an economy of force in that region.
The war for Ukraine is a case in point. A geopolitically independent, economically stable, and militarily confident Ukraine would separate a revanchist Russia from the West, establishing a buffer of sorts. It would also allow Europe and the United States to enjoy an economy of force in the region, continuing the security posture of the past decades characterized by anemic defense expenditures, limited and decreasing presence of American military might in the region, and the freedom to focus on other regions or issues.
For those in the West who are willing to restore the status quo ante in Ukraine and in the wider region, the initial question—how does one compete for the restoration of a buffer?—is pertinent. A small episode in Roman history can provide some guidelines. As we now have Ukraine and Russia, Rome had Armenia and Parthia.
Parthia was Rome’s rival in Asia. But Rome had a relatively thin military presence in the region and no troops in Armenia. Preoccupied with its vast empire and lengthy frontiers, Romans seemed to have been counting on Armenia’s desire to maintain its own independence and a corresponding willingness to put up a fight in case of Parthian advances. They also hoped that Parthia, weakened by internal strife, would be reluctant to expand its influence too close to the Roman Empire, thus escalating tensions and risking a war. Armenia served as a buffer state, under neither Parthian nor Roman direct control, independent enough to care for its own autonomy and yet dependent on the adjacent great powers’ will to maintain stability.
The metric of success for the Armenian buffer was obviously the absence of a war between the rival great powers. But for Rome one crucial metric of success was also its ability to leave Anatolia and Syria relatively undefended, with most of the legions deployed along more restless frontiers such as the Rhine and Danube. For the buffer to fulfill this role, Rome had to ensure that Armenia would not fall under the control of Parthia, whose forces were much closer. The way to achieve this was to ensure that the ruler of Armenia was friendly to Rome. Thus was balance maintained: Rome had an ally in the buffer state’s leader, Parthia its forces on the buffer state’s border. By intervening in Armenia in 58 AD and replacing a pro-Roman leader with one more servile to Parthia, the Parthian Arsacids altered this delicate arrangement.
This relatively small Parthian move, and the resulting change in the internal political posture of Armenia, led to…