Patronage is the power of a political official to fill government positions with people of their choosing. In many cases this leads to nepotism and favoritism.
In the U.S., there have been many fights against patronage since the mid-1800s. After the assassination of James Garfield by a man who was overlooked for a patronage-given position, many laws were formed to force officials to be qualified to do their job. Major patronage systems in the U.S. lasted until about the 1970s, when Chicago ended theirs.
Although often associated with corruption, patronage is not always seen as a negative. Many government positions are allocated through the patronage system, including many appointed by the President.