The Casualty Gap is a commendable and in some ways impressive book; it is also an example of political science at its most frustrating. For those with the patience to wade through its jargon-laced and data-laden pages, the book reveals disturbing—although by no means surprising—truths about exactly who pays the price for this country’s ever-growing propensity for war. Yet the single-mindedness with which Douglas Kriner and Francis Shen pursue their subject ultimately limits the value of the enterprise. The analytical rigor that unearths small but important insights impedes recognition of vastly larger ones. A preoccupation with nuance begets myopia. Hewing to the standards of their discipline, Kriner and Shen seem oblivious to the larger implications of their findings.

In Fahrenheit 9/11 (2004), his savage indictment of the global "war on terror," Michael Moore charged that the burden of wartime service and sacrifice was not exactly falling evenly across the spectrum of American society. George W. Bush marketed the campaigns launched in the wake of September 11 as democratic crusades. According to Moore, they actually conformed to the classic definition of "rich man’s war and poor man’s fight." When it came to fighting and dying, Moore argued, Americans near the bottom of the socioeconomic heap were doing more than their fair share. Meanwhile, those nearer the top—the offspring of the political class not least of all—were largely shielded from the wars’ effects. In an especially memorable segment, Moore showed that the military seemingly endorsed this arrangement: in search of warm bodies to ship to the combat zone, recruiters specifically targeted kids with few apparent prospects for making it back on the block.

Kriner and Shen possess little of Moore’s penchant for self-aggrandizing theatrics. Yet by cross-referencing official casualty records with Census data, they reach a conclusion that affirms Moore’s verdict: "when America goes to war, it is the poorer and less educated in society who are more likely to die in combat." Furthermore, this gap is by no means a recent development. Kriner and Shen survey the pattern of US military fatalities in four conflicts, beginning with World War II and proceeding to Korea, Vietnam and Iraq. (Regarding the distribution of casualties in earlier US history—during the Civil War, for example—the authors are silent.) Only in the case of the war against Germany and Japan did "the nation’s long-held norm of equal sacrifice in war" prevail. Given the reliance on conscription to raise the very large forces required for that conflict along with the military’s refusal to induct anyone who didn’t meet strict, if arbitrary, health and literacy standards, "the poorest and most undereducated counties actually suffered lower than average casualty rates." In 1941–45, there was no casualty gap. During the cold war, fairness vanished. With the US intervention in Korea, Kriner and Shen write, "the data show a dramatic change: strong, significant, socio-economic casualty gaps begin to emerge." The evidence they amass strongly suggests that this gap widened further during Vietnam and became greater still when the Bush administration invaded Iraq.

Between the early 1940s and 2003, the composition of US fighting forces—particularly those committed to ground combat—had changed considerably. During World War II, the vast majority of frontline troops were conscripts. By the time of Iraq, the Pentagon relied entirely on volunteers. In the interim, the Army had waged limited war with a mix of volunteers and draftees. The trend away from conscription benefited the haves more than the have-nots, according to Kriner and Shen. An "increasing reliance on volunteers," they write, "correlates strongly with the emergence of the casualty gap."

The peculiarities, not to say inequities, of conscription during the cold war only made things worse. With the size of the service-eligible cohort exceeding the military’s needs—neither Korea nor Vietnam required forces anywhere nearly as large as those mobilized for World War II—federal authorities took it upon themselves to decide who should serve when not all were needed to serve. The result was to institute mechanisms called deferments, which the talented and upwardly mobile proved adept at exploiting to dodge the draft.

The collapse of conscription under the weight of Vietnam seemingly made self-deferment an option open to all. The creation of the All-Volunteer Force in 1973 did little to close the casualty gap, however. Among the factors determining individual propensity to enlist, economic considerations became paramount. In some instances, patriotism and a desire for self-actualizing experience might play a role—Pat Tillman didn’t walk away from an NFL career to become an Army Ranger because he needed to enhance his gridiron skills on the military’s dime. Yet any recruiting sergeant worth his salt understands that nothing does more to lure interested youngsters to his door than high civilian unemployment combined with the promise of generous military pay and benefits. Whether before 9/11 or after, those with attractive alternatives to military service by and large have chosen them. Those without them signed up.

Who cares if "poorer and less-educated citizens are more likely to die in America’s wars than richer and more educated citizens"? We all care, Kriner and Shen insist: "Americans are disturbed by casualty inequalities." Citing the results of an imaginatively constructed survey, they suggest that public awareness of the casualty gap can reduce popular willingness to support interventionist policies or to fight on regardless of cost. Once sensitized to this pattern of unequal sacrifice, Americans "drastically change their military policy preferences" and become "much less willing to accept large numbers of casualties in future military endeavors." Put simply, as people become conscious of the casualty gap, they become more dovish.

For Kriner and Shen, the policy implications are clear: citizen awareness of the casualty gap can serve as a "democratic brake," helping to avert ill-advised or unnecessary wars. The key to activating this brake, they believe, is to "encourage an open discussion of how the burden of wartime sacrifice…is borne differently across the country." Open discussion will raise public consciousness, constraining warmongering policy-makers as a result. Would that such expectations were even remotely plausible. The authors’ faith in the power of "open discussion" is touching but profoundly naïve.

Recall that inequality of service and sacrifice is not exactly a deep, dark secret. After all, millions of people saw Fahrenheit 9/11 and absorbed its angry message. Nor has Michael Moore been alone in complaining that a fundamental unfairness pervades the way the United States has come to wage its wars. Yet the ensuing "discussion" has not notably reduced Washington’s inclination to use force—it certainly didn’t prevent Barack Obama from escalating US military involvement in Afghanistan by "surging" an additional 30,000 reinforcements. Even if knowledge of the casualty gap induces a certain unease, that alone does not suffice to change policy. If anything, policy-makers have displayed a considerable aptitude for ignoring qualms of conscience.

Although Americans more generally might bemoan the casualty gap, they won’t exert themselves to close it. The reason seems quite clear. Casualties affect public perceptions of policy when they hit close to home, when the sense of loss is direct, immediate and palpable. Yet the communities on whom the burden of sacrifice falls most heavily are precisely those that wield the least clout. Not having much money, they are easily ignored. "Citizens from low-income, low-education communities," Kriner and Shen write, "are disproportionately less engaged in politics than their fellow citizens from socio-economically advantaged communities." "Less engaged" is, to put it mildly, an odd formulation. The plain fact is that in Washington the less affluent are less likely to get a hearing. "The populations with the most to lose in war become those communities with the least to say to their elected officials." That’s one way to put it. Another is that these communities are most easily blown off.

The way to activate a democratic brake is to ensure that all Americans bear the brunt of war. Promoting awareness of the casualty gap won’t do that. Hitting Americans where it hurts—in the pocketbook—just might. Contemplate, for example, the political implications of funding war on a pay-as-you-go basis. After 9/11, the Bush administration employed tax cuts to purchase popular acquiescence in its plan for open-ended global war, freeing the present generation from any obligation to cover the financial costs incurred. Revoke that arrangement and the public’s willingness to indulge in further military adventurism will evaporate.

Consider the following back-of-the-envelope calculations. Since 9/11, the Pentagon budget has more than doubled to approximately $700 billion per year. Let’s peg current war costs at $400 billion annually (almost certainly a lowball estimate). There are approximately 150 million single or jointly filing taxpayers in this country. Reduce that number by the 30 million veterans who have already given at the office, as it were, and the per capita cost of ongoing US wars comes to more than $3,300 per annum. Add that as a surcharge to every American’s tax bill (or subtract that amount from the annual payout to Social Security recipients), and the "democratic brake" will bring American wars to a screeching halt.

This isn’t going to happen, of course. Officials in Washington, Kriner and Shen observe, "have a keen interest in reducing the visibility of casualties for fear that greater public exposure will minimize their freedom of action." The casualty gap is "an inconvenient truth" that both parties choose to ignore. For the same reason, officials have a keen interest in concealing war’s fiscal implications. They do this by pretending that there are none. Sustaining that pretense works in the near term to preserve the status quo.

This status quo—which includes grotesque inequality at home and perpetual war abroad—persists not because Americans are insufficiently alert to reality but because the powerful are determined to preserve arrangements that serve their own interests. After all, for the rich and the well-connected, inequality translates into privilege. Those who enjoy these privileges—and the politicians who do their bidding—are determined to retain them.

According to Kriner and Shen, "The idea that poorer segments of the country bear a disproportionate share of the nation’s sacrifice on the battlefield is antithetical to American democratic norms." This is not political science but wishful thinking. However regrettable, the fact that poorer segments of the country bear a disproportionate share of wartime sacrifice is entirely consistent with the actual practice of American democracy.