Charles Sumner was inaugurated upon President Fremont's death in 1873. He would serve a short term dying in office the following year. During his short term the 13th amendment was ratified.
Panic of 1873
That year was the beginning of a depression. Sumner vetoed a bill increasing the currency in order to stop inflation.
Charles Sumner died while still trying to pick an acceptable vice president, giving the presidency to President Pro Tempore of the Senate Matthew Carpenter. However, the law established that in this case a by election would be held that year to choose a president for a 4 year term.