James Gillespie Blaine (January 31, 1830 – January 27, 1893) was an American statesman and Republican politician who represented Maine in the United States House of Representatives from 1863 to 1876, served as Speaker of the House from 1869 to 1875, and was a U.S. Senator from 1876 to 1881. He served twice as Secretary of State, under presidents James A. Garfield and Chester A. Arthur in 1881, and under Benjamin Harrison from 1889 to 1892. Blaine was one of only two Secretaries of State to serve under three presidents, the other being Daniel Webster. He sought the Republican presidential nomination in 1876 and 1880, and received the nomination in 1884, narrowly losing the general election to Democratic nominee Grover Cleveland by approximately 1,000 votes. Blaine was a prominent figure in the moderate faction of the Republican Party, known as the "Half-Breeds".

Born in West Brownsville, Pennsylvania, Blaine moved to Maine after college, where he worked as a newspaper editor in Augusta before entering politics. Contemporary sources described him as an effective public speaker during an era when oratory was highly valued in American politics. He supported Abraham Lincoln and the Union cause during the American Civil War, and during Reconstruction he advocated for voting rights for freed slaves while opposing some of the more punitive measures favored by Radical Republicans. His economic positions evolved from supporting high tariffs to favoring reduced tariffs and expanded international trade. Throughout his career, Blaine faced allegations of improper financial dealings with railroad companies, particularly concerning the Mulligan letters. While these allegations were never substantiated with conclusive evidence, they became a significant issue in his 1884 presidential campaign.

As Secretary of State, Blaine advocated for expanded American involvement in international affairs, marking a shift from the more limited foreign policy approaches of previous decades. He promoted increased trade relationships, particularly with Latin American nations, and supported policies that came to be known as tariff reciprocity. His diplomatic approach emphasized American commercial interests and included support for territorial expansion in the Caribbean and Pacific regions. His foreign policy initiatives contributed to the development of more assertive American international engagement that would be further expanded during and after the Spanish–American War.

James Gillespie Blaine was born January 31, 1830, in West Brownsville, Pennsylvania, the third child of Ephraim Lyon Blaine and his wife Maria (Gillespie) Blaine. He had two older sisters, Harriet and Margaret. Blaine's father was a western Pennsylvania businessman and landowner, and the family lived in relative comfort. On his father's side, Blaine was descended from Scotch-Irish settlers who first emigrated to Pennsylvania in 1745. His great-grandfather Ephraim Blaine served as a Commissary-General under George Washington in the American Revolutionary War. Blaine's mother and her forebears were Irish Catholics who immigrated to Pennsylvania in the 1780s. Blaine's parents were married in 1820 in a Catholic ceremony, although Blaine's father remained a Presbyterian. Following a common compromise of the era, the Blaines agreed that their daughters would be raised in their mother's Catholic faith while their sons would be brought up in their father's religion. James Blaine's cousin, Angela Gillespie, was a nun and founded the American branch of the Sisters of the Holy Cross. In politics, Blaine's father supported the Whig Party.

Blaine's biographers describe his childhood as "harmonious," and note that the boy took an early interest in history and literature. At the age of thirteen, Blaine enrolled in his father's alma mater Washington College, in nearby Washington, Pennsylvania. There, he was a member of the Washington Literary Society, one of the college's debating societies. Blaine graduated near the top of his class and delivered the salutatory address in June 1847. Blaine then considered attending Yale Law School, but ultimately decided against it, and moved west to find a job.

In 1848, Blaine was hired as a professor of mathematics and ancient languages at the Western Military Institute in Georgetown, Kentucky. Although he was only 18 years old and younger than many of his students, Blaine adapted well to his new profession. Blaine grew to enjoy life in his adopted state and became an admirer of Kentucky Senator Henry Clay. He also made the acquaintance of Harriet Stanwood, a teacher at the nearby Millersburg Female College and native of Maine. On June 30, 1850, the two wed. Blaine once again considered the study of law, but instead took his new bride to visit his family in Pennsylvania. They next lived with Harriet Blaine's family in Augusta, Maine, for several months, where their first child, Stanwood Blaine, was born in 1851. The young family soon moved again, this time to Philadelphia where Blaine took a job at the Pennsylvania Institution for the Instruction of the Blind (now Overbrook School for the Blind) in 1852, teaching science and literature.

Philadelphia's law libraries gave Blaine the chance to, at last, begin to study the law, but in 1853 he received a more tempting offer: to become editor and co-owner of the Kennebec Journal. Blaine had spent several vacations in his wife's native state of Maine and had become friendly with the Journal's editors. When the newspaper's founder, Luther Severance, retired, Blaine was invited to purchase the publication along with co-editor Joseph Baker. He quickly accepted, borrowing the purchase price from his wife's brothers. In 1854, Baker sold his share to John L. Stevens, a local minister. The Journal had been a staunchly Whig newspaper, which coincided with Blaine's and Stevens' political opinions. The decision to become a newspaperman, unexpected as it was, started Blaine on the road to a lifelong career in politics. Blaine's purchase of the Journal coincided with the demise of the Whig party and the birth of the Republican party, and Blaine and Stevens actively promoted the new party in their newspaper. The newspaper was financially successful, and Blaine was soon able to invest his profits in coal mines in Pennsylvania and Virginia, forming the basis of his future wealth.

Blaine's career as a Republican newspaperman led naturally to involvement in party politics. In 1856, he was selected as a delegate to the first Republican National Convention. From the party's early days, Blaine identified with the conservative wing, supporting Supreme Court Justice John McLean for the presidential nomination over the more radical John C. Frémont, the eventual nominee. The following year, Blaine was offered the editorship of the Portland Daily Advertiser, which he accepted, selling his interest in the Journal soon thereafter. He still maintained his home in Augusta, however, with his growing family. Although Blaine's first son, Stanwood, died in infancy, he and Harriet had two more sons soon afterward: Walker, in 1855, and Emmons, in 1857. They would have four more children in years to come: Alice, James, Margaret, and Harriet. It was around this time that Blaine left the Presbyterian church of his childhood and joined his wife's new denomination, becoming a member of the South Parish Congregational Church in Augusta.