The U.S. census is an enterprise so dull that the sheer size and scope of the dullness are exhilarating. Just processing the data from the census of 2010 will take until the end of 2013. Amid the deluge of numbers and slick visualizations, the language of the project will be largely forgotten, which is for the best in the case of the survey questions themselves. The use of the word Negro in question 9, the awkward designations for persons of “Hispanic, Latino, or Spanish origin” in question 8, and the lack of options for transgender individuals in question 6 all sparked predictable controversies last year.

Worth saluting, by contrast, is the bizarrely compelling rhetoric surrounding the decennial questionnaire. Nowhere is the beauty of the banal so apparent as in the slogans, mailings, and brochures of the U.S. Census Bureau. The taglines churned out by its public-relations program—from you can know your country only if your country knows you (1940) to it counts for more than you think (1990)—represent each decade’s best effort to say nothing, offend nobody, and motivate everyone. Literally. The goal is to reach all 300 million people living in the United States, and motivation is key because for every 1 percent increase in participation, the government saves $85 million. That makes census sloganeering some of the highest-stakes wordsmithing around.

The sentences coined in this crucible have come to follow identifiable conventions. Their diction is almost universally simple: contractions, colloquialisms, monosyllables, and puns are the norm, as in answer the census! we’re counting on you! (1980). The address tends to be first- or second-person, and, in the longer examples, inverted and parallel constructions are common. Consider the you can know mantra from 1940—technically an antimetabole—or 2010’s we move forward when you send it back.

Nearly all of the 2010 taglines were typical in their compliance with these rules, but they were exceptional for the charm of their hypnotic bureaucratese, and for what they reveal about how we number ourselves.

be counted in 2010. This command, masked as an invitation, neatly captures the two-sidedness of population counting in general. When groups allow themselves to be tallied, they undergo a process of fruitful objectification: they submit to the labeling process in return for the ability to make demands and receive compensation. This four-word phrase reflects that balance of ­flattening and empowerment because it sounds deceptively like an offer. It also...