George B. McClellan Jr. was born on November 23, 1865, in Dresden, Saxony (Germany), where his parents were living temporarily after his father, General George B. McClellan Sr., the Democratic presidential nominee of 1864, lost his race for the White House.  Young McClellan was educated at St. John's Boarding School (Ossining, New York) and Princeton (1882-1886), and then spent two years on a grand tour of Europe.  Upon returning to the United States, he worked as a correspondent and editor for several New York newspapers, including the Herald, Morning Journal, and World.  

In 1889, McClellan joined Tammany Hall, the Democratic political machine of New York City, and served (1889-1893) in the patronage office of treasurer for the Brooklyn Bridge (which was a toll bridge until 1910).  He also attended New York Law School, passed the state bar in 1892 and established a practice in Manhattan.  He served as president of New York's Board of Aldermen (1892-1894), and was elected in 1894 to the first of five terms in Congress (1895-1903), where he opposed high tariffs and imperialism.  While there was some talk of McClellan as a Democratic vice presidential and presidential contender in 1900 and 1904, respectively, his lack of national stature and his association with Tammany Hall prevented such candidacies.  

In 1903, Tammany boss Charles F. Murphy convinced a reluctant McClellan to challenge the incumbent mayor, Seth Low, who had been elected in 1901 on a fusion ticket (note the broken wooden sword labeled "Fusion" in the cartoon).  In November 1903, McClellan handily defeated Low, 55%-45%, and resigned his congressional seat the next month.  Taking office in January 1904, the new mayor demonstrated his independence by selecting his own associates for top municipal positions, although appointing Tammany men to lesser posts.  

When this cartoon was published in the fall of 1905, McClellan was seeking reelection against Republican William Ivins and independent William Randolph Hearst, the controversial newspaper publisher who was endorsed by the Municipal Ownership League.  In November 1905, McClellan narrowly won a second term, edging Hearst 39%-38%, with Ivins taking 23% of the vote.  (The mayoral term had been expanded to four years.)

During his tenure as mayor (1904-1910), McClellan concentrated on improving the city's physical infrastructure by establishing the Catskills as a source of the city's water supply, expanding the rapid transit, and constructing roads, bridges, docks, schools, hospitals, and other buildings.  The expenditures produced massive debt for the city.  His second term was plagued by opposition from Hearst and Murphy.  The newspaper magnate charged McClellan with vote fraud in the 1905 election, and unsuccessfully petitioned for a recount.  In 1906, the mayor cracked down on vice, fired several corrupt city officials, and shut Tammany Hall out of patronage jobs, all of which caused Boss Murphy to work against him.

In 1908, McClellan began lecturing occasionally on public affairs at Princeton University, which appointed him as an economics professor in 1912.  He aroused criticism when he initially sympathized with the German position in World War I, but earned praise for serving in battle as a major after the United States declared war in 1917.  After the war, he returned to Princeton and published books on Italian history, society, and art.  In 1935, McClellan positively compared Italian dictator Benito Mussolini’s invasion of Ethiopia to the United States invasion of Mexico in 1846.  After retiring from Princeton in 1931, McClellan moved to Washington, D.C., where he became known for his lavish dinner parties and fine art collection.  He died a week after his 75th birthday, on November 30, 1940, and is buried at Arlington National Cemetery.