Thread by @jaylyall_red5

It's here! It's really here! My new book, Divided Armies, is now available from @PrincetonUPress as an e-book, soft-cover, and hardback.

Let me tell you a bit about the book. THREAD 1/11

amazon.com/dp/0691192448/…

What's it about? In a nutshell, I try to explain the battlefield performance of belligerents in modern wars since 1800. Lots of great work has focused on relative power, technology, regime type, or civil-military relations.

I take a different tack.

First, I argue that we've overlooked perhaps the key driver of battlefield performance: inequality. Specifically, prewar ethnic hierarchies within armies --- what I term "military inequality" --- shapes how armies fight and die. The worse the inequality, the worse the performance

We didn't have a measure of military inequality.

So I built one. Imagine an index that runs from 0 (perfect equality) to 1 (perfect inequality). If we know an army's ethnic makeup + how state treats each group (full rights, marginalized, or repressed), we know its MI

Details:

Second, I introduce a broader notion of how armies perform in wartime. I include behavior like mass desertion, mass defection, and the use of blocking detachment by armies to kill their own retreating soldiers.

Take military inequality, stir with new measures of battlefield performance, and what do you get? A new view of how rising levels of prewar inequality are associated with greater chance of lopsided casualties, mass desertion and defection, and shooting your own soldiers 👇

Third, the book rests in part on a shiny new dataset called Project Mars. 134 coders using 21 research languages worked nearly 7 years to gather and vet new data on belligerents & wars. The result? A much more global, much less Western, military history.

Meet the coders!

Fourth, I tried to break new ground in how we select cases for in-depth study. Rather than choose the usual suspects, I created four pairs of cases through matching & random sampling. Together, these cases are far more reflective of past (& future?) wars, covering 150 years.

Cases range from the Mahdiya, Kokand, and Morocco in the 19th Century to Ethiopia and DRC in the 1990s. In the final chapter, I apply the argument to 4 Soviet Rifle Divisions in the Battle for Moscow, using declassified sources to show how inequality matters within armies, too

The perils of military inequality are not confined to the past, tho. Inequality will shape how new tech like AI is fielded & its effects on armies, for example. Safeguarding its hard-won inclusion will be vital for the US if it is to avoid the historical fate of divided armies

Hopefully this thread gives a taste of the book's ambition. I'm grateful to everyone who offered feedback, my RAs, the blurbers (@mchorowitz @CastilloJasen @KoriSchake David Laitin Stan McChrystal) & my editors @e_crahan & @bridgetfmccoy for taking a chance on a (very) big book.