Calvin Coolidge (born John Calvin Coolidge Jr.; ; July 4, 1872 – January 5, 1933) was the 30th president of the United States from 1923 to 1929. A Republican lawyer from New England, born in Vermont, Coolidge worked his way up the ladder of Massachusetts state politics, eventually becoming governor of Massachusetts. His response to the Boston Police Strike of 1919 thrust him into the national spotlight and gave him a reputation as a man of decisive action. The next year, he was elected the 29th vice president of the United States, and he succeeded to the presidency upon the sudden death of Warren G. Harding in 1923. Elected in his own right in 1924, he gained a reputation as a small-government conservative and also as a man who said very little and had a dry sense of humor, receiving the nickname "Silent Cal". He chose not to run again in the 1928 election, remarking that ten years as president was (at the time) "longer than any other man has had it – too long!"

Throughout his gubernatorial career, Coolidge ran on the record of fiscal conservatism and strong support for women's suffrage. He held a vague opposition to Prohibition. During his presidency, he restored public confidence in the White House after the many scandals of his predecessor's administration. He signed into law the Indian Citizenship Act of 1924, which granted US citizenship to the indigenous peoples of the United States, and oversaw a period of rapid and expansive economic growth in the country, known as the "Roaring Twenties", leaving office with considerable popularity. He was known for his hands-off approach to governing and for his pro-business stances. As a Coolidge biographer wrote: "He embodied the spirit and hopes of the middle class, could interpret their longings and express their opinions. That he did represent the genius of the average is the most convincing proof of his strength."Scholars have ranked Coolidge in the lower half of U.S presidents. He gains almost universal praise for his stalwart support of racial equality during a period of heightened racial tension in the United States, and is heavily praised by advocates of smaller government and laissez-faire economics, while supporters of an active central government generally view him far less favorably. His critics argue that he failed to use the country's economic boom to help struggling farmers and workers in other flailing industries. There is also still much debate between historians as to the extent Coolidge's economic policies contributed to the onset of the Great Depression. However, it is widely accepted, including by his own Presidential Foundation, that the Federal Reserve System under his administration was partly responsible for the stock market crash of 1929 that occurred soon after he left office, which signaled the beginning of the Depression.