Social scientists have access to a lot of meaty data on state military recruitment. But recruitment by non-state forces in civil wars is another story. Rebel movements usually keep fairly poor records and for good reason: If they lose, having a well-maintained spreadsheet of their fighters for their enemy to find won’t extend any lifespans. Trying to figure out who actually does the fighting in civil wars — and why —  is an ongoing challenge for conflict scholars and the subject of the next couple editions of Deep Dive.

One way to approach the problem is to focus on old wars. In the latest issue of the American Political Science Review, Andrew Hall, Connor Huff and Shiro Kuriwaki went all the way back to the American Civil War to answer a question that’s at the core of how the Confederacy built its army: Did slave ownership make people more or less likely to join the Confederate army?

At first, this might seem like an idiosyncratic question: Slaveholders don’t make up a significant percentage of combatants in most modern wars. But in reality, it goes to the heart of a basic question about how rebel movements — that largely benefit upper classes — function. The Confederacy rebelled to preserve slavery, but, as Hall et al. write, “wealthy Southerners had incentives to free-ride on poorer Southerners and avoid fighting.” When upper-class interests are a rebellion’s cause, do they fight, or do they pay for poorer people to fight in their stead?

Hall et al. first had to figure out who actually fought in the Confederate army. They combined census documents, soldier lists, and the 1850 Slave Schedule, which lists enslaved people and slave owners, to make a dataset of nearly everyone, slaveholders and not, in the Confederate army. The dataset showed that, while non-slaveholders massively outnumbered slaveholders in the Confederate army and in the Confederacy overall, on a per-household basis, slaveholders actually contributed more soldiers to the rebellion than non-slaveholders did. Each non-slaveholding household produced 1.78 Confederate soldiers each, but households that enslaved between one and three people produced 2.04 Confederates each and households that enslaved over eight people produced 2.18.

Those numbers don’t necessarily mean, however, that the slaveholding households sent more soldiers to preserve their interests in maintaining human bondage. It could have been, for instance, that poorer, non-slaveholding households could less afford to send young people off to war. The researchers wanted to differentiate between people who were rich but did not own slaves and people who were slaveholders.

To do this, Hall et al. utilized data from the another indelible moral stain on American history: genocide against Native Americans. Georgia held a series of lotteries in the first half of the 19th century to award land taken from the Cherokee Nation to eligible white men on a random basis. By and large, men who won land in the lottery sold it off to speculators and very often used the proceeds to become slaveholders. Hall et al. measured the likelihood of lottery winners to send sons to fight for the Confederacy, and found them to be significantly more likely to do so than lottery losers. That is, adding wealth in the form of enslaved people made Southern whites more inclined to fight a war to defend slavery.

Shirin Jaafari spoke to American Muslims who are struggling to balance their desire to undertake the hajj, the pilgrimage to Mecca expected of Muslims at least once, with their disdain over some of Saudi Arabia's actions. Between the Saudi government being responsible for mass civilian casualties in Yemen, the murder of journalist Jamal Khashoggi, and other crackdowns on activists, some Muslims feel that it would be wrong to spend their money in Saudi Arabia, even to fulfill one of the key tenets of their faith.

Tristan Guyette, recently returned from the annual progressive confab Netroots Nation, called on his fellow activists not to ignore foreign policy issues in their list of political priorities. Foreign policy discussions were marginalized at the conference, but, Guyette argued, it is impossible to get a handle on core progressive issues like immigration and federal spending for domestic programs without thinking about the foreign policy aspects of those issues.

North Korea held municipal elections last weekend, and Patrick Winn explained how the balloting works. Elections serve to demonstrate unity, so everyone over 17 is required to vote. Ballots consist of a page with a single name and voters can choose to submit their ballot unmarked — a vote for the candidate — or to cross out the candidate’s name, demanding a new choice. Hardly anyone crosses out the name, and the consequences for doing so are likely dire. But once voting is complete, the party can begin — unlike in the US, election days in North Korea are national holidays.

It was a big week for security wonk-friendly movie trailers last week, from the new “Top Gun” to, uh, “Cats.”

Intro IR professors: You can now replace an entire week of your course lectures with this one meme. You’re welcome.

The Gen Z State Department will be unstoppable.

As FaceApp took over the internet last week, some warned that it was an attempt by a Russian company to get access to your photos for various nefarious purposes. What kinds of purposes, you ask? Mostly a global conspiracy to prove you like Skrillex.

Britain’s defense ministry must grow its strategic eyeliner reserve, as Brexit threatens supply chains.

Turkey went through with its promise/threat to take delivery of Russian S-400 air defense systems despite the Pentagon’s promise that, as much as Turkey wants to buy both the S-400 and the American F-35 Joint Strike Fighter, never the twain shall meet. Some Turks were more excited than you might expect about their country acquiring some anti-aircraft missile. The Pentagon did block F-35 sales to Turkey in response, prompting last week's winner for best alternate headline writing. 

True story: Coca-Cola used to be based on the Georgia coast, and only moved to Atlanta in 1989 when Pepsi acquired a robust shore bombardment capability.

Correction of the week/year.

Yo dawg, I heard you liked Soviet military vehicles, so I put a Soviet military vehicle on your Soviet military vehicle.