In the past month, President Trump claimed widespread voter fraud due to mail-in voting warrants a delay of November’s election. He even admitted on Thursday that he opposes emergency funds for both states and the U.S. Postal Service to limit Americans’ ability to vote by mail. But undermining the Postal Service is more than a political tactic. It is an attempt to undermine an institution that has been a crucial pillar of American democracy for longer than we have been a nation.

Attacking the Postal Service is an attack on democracy itself — something the Founders understood. They recognized the significance of the Postal Service, understanding a functioning and safe means of communication was central to democracy, and as we are learning in a pandemic, it remains just as essential now.

In some of the first meetings of the Continental Congress, in July 1775, a year before that body would even declare independence, the rebel leaders needed a safe way to communicate. Concerned that loyalist postal clerks would pry into their correspondence, they created what they would call the Constitutional Post, stretching from what is now Maine to Georgia, led by the first postmaster general, Benjamin Franklin.

The postal system served a critical function holding the colonies together against the British superpower. As David Ramsay, historian of the revolution would proclaim, in terms of independence, “the pen and the press had merit equal to that of the sword.” The army alone could not have won the war “unless the great body of the people had been prepared for it, and also kept in a great disposition to oppose Great Britain.”

After independence, James Madison, the future president who was then a member of Congress, observed the post system had become “the principal channel through which a general knowledge of public affairs, was diffused.” For Madison, the circulation of newspapers and correspondence throughout the 13 states was “justly reckoned among the surest means of preventing the degeneracy of a free Gov’t.” It would also connect members of Congress to their constituents so that those constituents would know the workings of their representatives, subjecting “every salutary public measure to the confidence & cooperation of all virtuous Citizens.”

Madison was not alone in seeing the postal system as an essential foundation for the Republic. In 1791, in his Third Annual Message to Congress, George Washington advocated for strengthening the postal system because “the expedition, safety, and facility of communication, is increased by” the postal system, which spreads “a knowledge of the laws and proceedings of the Government, which, while it contributes to the security of the people, serves also to guard them against the effects of misrepresentation and misconception.”

Thanks to this recognition of its importance, even as an upstart nation, the U.S. postal system rivaled that of the great powers at the time. On the eve of the Revolutionary War, there were just 67 post offices, or four for every 100,000 inhabitants, in the colonies. By 1828, however, there were 74 for every 100,000. The American system had twice as many offices as Britain, and five times as many as that of France. By 1831, the American system employed just over three-quarters of the entire federal civilian workforce, with more postmasters (over 8,700) than the number of soldiers in the federal army (6,332). Given its size and reach, the post office probably was the federal government to most Americans.

Partly because of the expansion of the postal system, the late 18th and early 19th centuries saw the growth of national movements that were linked to the physical spread of post offices and postal routes, like the Independent Order of Odd Fellows and the Young Men’s Christian Association. As new settlers arrived in places and created communities or strengthened existing ones, they brought with them their experience in and taste for the civic life they enjoyed in their previous hometowns. Leaders of organizations “back home” would send information to these settlers through the mail telling them how to set up a local chapter, and the growth of these organizations tracked the spread of the postal system.

The robust development of the postal system also empowered political speech and social movements, none more so than the abolitionist movement that emerged in the mid-1830s even though anti-slavery groups had existed in the United States much earlier. Critical to the movement’s advocacy was the emergence of a new, steam-powered printing press that made printing faster and far less expensive. The combination of the postal system and steam power, what proslavery Congressman John Winston Jones (Va.) would call the “great revolutionizers of the world,” threatened to undermine the institution of Southern slavery.

So dangerous did enslavers see such mailed materials that President Andrew Jackson and Postmaster General Amos Kendall, both of whom enslaved people, directed postmasters not to distribute abolitionist mailings in the South.

The use of the mails to communicate, coordinate, persuade and cajole was popular with social movements throughout the 19th and 20th centuries. Progressive Era organizations seeking political reforms in the first part of the 20th century, the American Legion promoting the passage of the G.I. Bill in 1944 and the 1,000 local chapters of the NAACP advocating for the end of the Jim Crow system all used the mail to instruct and inform their membership and keep abreast of threats and opportunities to advance social change.

But while liberal social movements used the mail to foment political change, nothing about the tactic was inherently liberal. In fact, in the late 1960s and early 1970s, conservative voices, frustrated that the liberal press was not giving their ideas adequate airtime on radio and television, essentially invented the concept of modern direct mail. Richard Viguerie, who got his start as a marketing professional, created one of the first computerized mailing lists, which he turned into a political tool. Viguerie and his allies began using the list to micro-target conservative messages, ranging from advocacy against the Soviet Union and the spread of communism to promoting the antiabortion cause, to potential supporters who might find them attractive.

This tactic helped launch the Reagan Revolution and build grass-roots organizations like the Moral Majority that were pillars of the movement. Indeed, conservatives revolutionized this style of political communication, and the 500,000-strong mailing list of the National Federation of Republican Women and later that of Phyllis Schlafly’s Eagle Forum became powerful tools for elevating conservative voices.

These examples across American history reveal the U.S. Postal Service’s nonpartisan role in facilitating the functioning of the uniquely American democracy.

It may play an even more central role in our democracy today as a pandemic threatens another pillar of our political system: the sanctity of the vote. Efforts to undermine the postal service threaten to undermine democracy itself, and while the USPS may seem less important in the digital age, its publicly funded nature — which forces it to focus on the public good — and reach into all American communities makes it just as important today as when Madison and Washington extolled its virtues.