According to the most recent analysis by the National Assessment of Educational Progress, only 13 percent of eighth graders are proficient in U.S. history — down from a peak of 18 percent in 2014. A mere 22 percent of those students are proficient in civics, the first decline since the test began in 1998.

Adults fare little better. Less than half of those surveyed could name the three branches of government (1 in 4 could not name any). Nor did they know that a 5-4 Supreme Court ruling becomes the law of the land.

Yet, even as Americans across the political spectrum believe that more civic awareness could help heal the country’s divides, only seven states require a full year of civics education.

The belief that an educated citizenry is the best protection for democracy is as old as the Republic. As George Washington asked in the founding era: “What species of knowledge” is more important than “the science of government?”

Yet, U.S. history and civics curriculums have long been attacked from the political right as insufficiently patriotic and from the left as woefully incomplete and discriminatory. In short, Americans have never agreed about what should be taught when it comes to our nation’s history and government. And as this latest round of test scores suggests, that has real implications for schoolchildren.

How to teach American history and civics was not initially an issue of national debate or concern. At the nation’s founding, most Americans received little or no formal schooling, but learned instead from family, work and church.

That began to change with the adoption of universal, state-funded education. By the 1840s, education reformers like Horace Mann argued that publicly supported schools could help to create “disciplined, judicious, republican citizens” by “teaching the basic mechanics of government and imbuing students with loyalty to America and her democratic ideals.”

To protect public schools from “the tempest of political strife,” fears spurred in part by the arrivals of immigrants, Mann insisted civics be presented in a nonpartisan, nonsectarian manner — even as he and his allies, consciously or not, imbued their own values into this supposedly neutral curriculum. Civics was taught through study, memorization and recitation of patriotic speeches and foundational texts, such as the Declaration of Independence and U.S. Constitution. These exercises were paired with readings from the King James Bible “that exemplified the Protestant ethic.”

Unsurprisingly, controversies arose. Abolitionists complained that the nonpartisanship required the exclusion of anti-slavery principles. Catholic leaders attacked non-sectarianism as a stealth imposition of Protestantism, prompting “school wars” that led to the creation of the Catholic parochial school system.