Joseph M. Adelman is a historian of the politics and media of the American Revolution. He is a National Endowment for the Humanities fellow at the American Antiquarian Society.

This week the U.S. Senate is debating the 21st Century Postal Act of 2011, a proposal to reform the U.S. Postal Service and change the way the USPS does business in order to make it more profitable. In December, the Postal Service proposed to cut Saturday delivery, close half of its 500 processing centers around the country and dozens of local post offices, and lay off thousands of workers. The bill under consideration this week would delay closures and require studies to determine how best to proceed with any reductions in delivery. Although those are laudable goals, they will not solve the fundamental problem: Congress assumes that this vital government service will somehow become profitable.

In the midst of a long decline in the volume of mail, the demise of the Postal Service -- at least as a public institution with universal service throughout the United States -- often seems inevitable. Yet the critiques and suggestions offered as solutions for what ails the Postal Service see the problem only in terms of commercial and financial concerns. The circumstances of the Post Office's founding suggest a far broader and more important mission: guaranteeing the sanctity of civic participation and political debate.

During the American Revolution, the post was a crucial point of contention between colonists and the Crown because it was the means for circulating not only correspondence but also newspapers, the lifeblood of intercolonial political cooperation. When British officials threatened the free circulation of news, newspaper publishers led the charge in 1774 to replace the British imperial system with a "Constitutional Post." Without a government structure, the post would be privately funded, but newspaper publishers and allies like the Boston Committee of Correspondence made sure that reliable, safe, and secure circulation of political intelligence was a primary function....