We're coming up on the Fourth of July, when the United States is full of barbecues, fireworks, parades, and competitive hot dog eating. But why do we say "the United States is full of..." instead of "the United States are"? On Independence Day, there's no better time to reflect on how the rise of America's national unity was mirrored by its grammatical unity, as "the United States" turned into a singular noun.

The late historian Shelby Foote repeated an oft-told tale for the popular documentary series The Civil War (first broadcast on PBS in 1990):

Before the war, it was said "the United States are." Grammatically, it was spoken that way and thought of as a collection of independent states. And after the war, it was always "the United States is," as we say today without being self-conscious at all. And that sums up what the war accomplished. It made us an "is."

Foote's tidy narrative is just a little too tidy, reiterating conventional wisdom that has been floating around since a couple of decades after the end of the Civil War. In 1887, a Washington Post writer declared that the Civil War "settled forever the question of grammar... The surrender of Mr. Davis and Gen. Lee meant a transition from the plural to the singular." Four years later, clergyman G. H. Emerson wrote that "the change from the plural to the singular was vital, though it has taken a War of Rebellion to make the difference unmistakable." And in 1909, classics scholar and former Confederate soldier Basil Lanneau Gildersleeve stated, in a widely quoted lecture, "It was a point of grammatical concord which was at the bottom of the Civil War — 'United States are,' said one, 'United States is,' said another."

Rather than just accepting such sweeping claims, one writer sought to track the actual shift in usage from "the United States are" to "the United States is." In 1901, former secretary of state John W. Foster contributed an article to the New York Times finding that the transformation from plural to singular was a slow and messy one. In the Constitution, for instance, "the United States" is treated as plural, but so is "the House of Representatives," "the Senate," and "Congress." Over time, usage changed in American English, so that these collective nouns became construed as singular. (In British English, collective nouns can still take plural verb forms.) "The United States" also went the singular route, but its path was complicated by the plural ending -s at the end of "States."

Foster shoots down the popular notion that the Civil War was wholly responsible for the change in thinking. Before the war, there were writers and statesmen who preferred the singular, and afterwards there were still many who held on to the old plural usage. You can see the persistence of the traditional plural treatment of "the United States" in the 13th Amendment, ratified at war's end in 1865:

Neither slavery nor involuntary servitude, except as a punishment for crime whereof the party shall have been duly convicted, shall exist within the United States, or any place subject to their jurisdiction.

In fact, the "United States is/are" debate raged for decades and was hardly settled by the surrender of the Confederacy. An 1895 column in the Indianapolis Journal defended the usage of Secretary of State Richard Olney, who preferred "the United States are." The writer insisted that this was correct usage on grammatical grounds: "Thoroughly as one may believe in the idea of nationality, one cannot ignore the structural principles of the English language." As late as 1909, Ambrose Bierce was clinging to this grammatical defense of "the United States" as plural. In his peevish compendium Write it Right, Bierce griped, "Grammar has not a speaking acquaintance with politics, and patriotic pride is not schoolmaster to syntax."

But Bierce was on the losing side of that argument. Already, as a result of Secretary Foster's careful historical research on the subject, the House of Representative's Committee on Revision of the Laws had ruled in 1902 that "the United States" should be treated as singular, not plural. The tide had finally turned — four decades after the Civil War.

(Bierce might have been a stick in the mud on this issue a century ago, but he was an entertaining stick in the mud nonetheless. He's always a pleasure to read even when he's dead wrong. That's why I'm looking forward to the new edition of Write it Right to be published later this year, edited and annotated by Jan Freeman, language columnist for the Boston Globe. Today's grammar grouches could learn a thing or two from ol' Ambrose.)