1883 Further restrictions on soliciting campaign donations with the Civil Service Reform Act

The political patronage system, in which favors and federal jobs were promised in exchange for donations, remained alive and well during much of the 19th century, having originally taken root in the Jackson era. New government appointees were often large campaign contributors and financiers; in effect, government was for sale.

Pressure to change the system reached a tipping point after Charles Guiteau, a prospective government administrator who was denied a position, assassinated President Garfield in 1881. In 1883, the Civil Service Act (or the Civil Service Reform Act, as it's more commonly known today), overhauled the government's party composition by prohibiting positions from being filled by employees who had specific political ties or party affiliations, and mandated that jobs had to be given based on merit. It also created the Civil Service Commission to enforce the new law; the commission existed until 1978, when it was split into the Office of Personnel Management and the Merit Systems Protection Board.

That said, ambassadorships are often given to major bundlers and presidential supporters: See the contribution records for Obama administration appointees. Ambassadors are exempt from the Civil Service Act, and it's a time-honored tradition for presidents to reward their biggest backers with these plum positions.