Why wasn't Teddy Roosevelt allowed to fight in World War One? (Short Animated Documentary)

TL;DR

Wilson blocked Roosevelt from fighting in WWI primarily out of political self-interest, fearing Teddy's heroism or death would destroy Democratic ambitions.

Key Points

• 1.Roosevelt had genuine military credentials and personal motivation to fight. A hero of the Spanish-American War at San Juan Hill, he resigned as Assistant Secretary of the Navy to volunteer in 1898, and by 1917 wanted to die gloriously rather than succumb to diseases contracted in South America.
• 2.Congress effectively passed a law designed specifically to let Roosevelt fight. The Selective Service Act of May 1917, backed by Senator Warren G. Harding, authorized a 70,000-man volunteer force; everyone in Congress understood Roosevelt would lead it to France as a vanguard for the Allies.
• 3.The military raised practical objections about his fitness and tactical relevance. At 58, partially blind, and frequently ill, generals feared his 1898 mindset was incompatible with modern trench warfare, and his undefined rank made it impossible to discipline a former commander-in-chief without destroying public morale.
• 4.Wilson's core reason for refusal was pure political calculation. Having barely won in 1916 and eyeing a third term, Wilson knew a heroic Roosevelt would be unbeatable as a Republican candidate, while a dead Roosevelt would make Wilson look reckless — either outcome was catastrophic for the Democrats.
• 5.Roosevelt died embittered in January 1919, weeks after the war ended. Two of his sons were wounded and one killed in the war he was barred from joining; he spent his final years attacking Wilson's League of Nations as toothless, preferring a 'league to enforce peace' with binding military intervention.**