Kennedy's assassination brought in the presidency of his vice president at the time, Lyndon B. Johnson. Johnson thus held the office prior to being elected; Johnson was elected for the first time in 1964, although he served as president from 1963-8.

In the years leading up to the Boxer Rebellion, both European and Japanese powers competed to establish spheres of influence in China, effectively taking control of much of the country's economy. The Boxers, or the Society of Righteous and Harmonious Fists, primarily wanted these foreign powers out. They did kill missionaries and take over embassies as well, but both of those tactics were seen as means to an end. The Boxer Rebellion should not be confused with Mao Zedong's communist takeover of China after World War II.

Mussolini came to power in Italy in 1922 as head of the Fascist Party and elected leader of the Italian government. Italy, at the time, was suffering from extreme economic hardship. Mussolini promised rapid economic growth and Italian territorial expansion. In 1925 Mussolini declared himself dictator for life.

Emiliano Zapata and Pancho Villa were both instrumental in the Mexican Revolution and the subsequent establishment of the Mexican Republic. Villa led the revolutionaries in northern Mexico, whereas Zapata led peasant rebellions in southern Mexico. Together they are more responsible than any other revolutionaries for the successes of the Mexican Revolution.

Throughout much of the 1960s public opinion of the Vietnam War was fairly evenly split, but it began to turn against the war in the late 1960s and this was compounded by the election of President Nixon. Within a year of Nixon’s election less than a third of the population was in support of the Vietnam War.

Mustafa Kemal led the Turkish independent movement following the destruction of the Ottoman Empire at the end of World War Two. He is credited with founding the Turkish Republic and he served as the first President of Turkey. His time in power is marked by a series of modernizing reforms, including universal public education and the elevation of the status of women.

Hitler came to power in Germany in 1933. He was appointed Chancellor of Germany by the President of the Weimar Republic. Once in power as Chancellor, Hitler and the Nazis worked to consolidate power and quickly quashed opposition. In 1934 they held a referendum in which Hitler was elected as dictator of the nation. The election was highly controversial and contentions as the Nazi Party worked to manipulate public opinion and suppress opposition.

The reform policies of glasnost and perestroika were initiated by Mikhail Gorbachev in the Soviet Union in the 1980s. The primary purpose of glasnost, which means "openness" was to improve the transparency of the Soviet political system and allow more people to be included in the political process.

The Qing Dynasty was the last dynasty of imperial Chinese history. In the early twentieth century civil disorder was breaking out all over China and the dynasty was replaced by the Republic of China (first in 1912, and then again in 1917) led by revolutionary leader Sun Yat-Sen. 

The Cultural Revolution in China was a time of widespread state-organized persecution and suppression of opposition. It might reasonably be compared to the Great Purge in the Soviet Union. The Great Purge took place from 1936 to 1938 and involved the suppression of peasants, the wholesale execution and restructuring of army leadership, and the forced imprisonment and torture of hundreds of thousands of people.