Once upon a time, American bureaucracy worked through patronage, an informal system of job-distribution by the party in power. If you helped elect somebody, you could get a job in return, often in the post offices spread across the length and breadth of the land. This very much inspired you to keep your representative in power, since the other party’s representative would instantly replace you.

Things began to change in the 1880s, when Congress voted in the Pendleton Act to establish a merit-based civil service protected from political shifts. By 1921, 80% of the civilian federal workforce was civil service. By then, too, the number of federal employees had grown fivefold. Progressive Presidents, especially Theodore Roosevelt, usually get the credit for this transformation of American government from “patronage to service,” often through executive orders.

Samuel Kernell and Michael P. McDonald dig into why members of Congress “chose to abandon an entrenched patronage system that had served them well in favor of one designed to insulate employees from their control.” They point to the rapid expansion of the federal government in response to “a growing appetite for constituency services within Congress that the patronage system was ill suited to deliver.” Constituents back home now wanted more than the occasional post office position. Kernell and McDonald take as their case study the introduction of rural free mail delivery (RFD), an enormously popular innovation, starting in the late 1890s.

Previous to RFD, rural residents went to the local post-office to pick up their mail. “Local” could be many miles away. There were some 77,000 rural postmasters, meaning each member of Congress had some 200-250 postmaster positions to divvy out. Incompetence and embezzlement amongst this crew were often protected because “Congressmen doted on their postmasters,” who also acted as local eyes and ears. Sometimes, the only way to dislodge a hack postmaster was to elect the other party, which was no guarantee of competence.

But rural residents knew that urbanites got their mail delivered at home; and they wanted the same service. The pressure for RFD built up over a long period. Congress heard the demand loudly and clearly: they “willingly, indeed eagerly, traded in their postmasters for mailboxes.” A couple hundred happy postmasters versus many thousands of happy voters in a district turned out to be no contest.

As Kernell and McDonald detail, the distribution of RFD routes was still deeply political, with Republicans and Democrats fighting over who was served in that “era of unparalleled partisanship.” But the politics had changed: a new breed of professional politician at the turn of the twentieth century saw “a greater electoral payoff in direct services to their districts than in subsidy of local party organizations.”