Ka kammala wannan magana: A shekara ta 1898, Rynning ya gano cewa an fara yaƙi da Spain kuma tsohon abokinsa, Kanar Leonard Wood, yana kafa rundunar sojan doki na sa kai, wanda daga baya aka san shi da Theodore Roosevelt's Rough Riders. Ya shiga aikin soja a matsayin mai zaman kansa kuma ya dawo daga yaki a matsayin mai kula da na biyu a cikin Bungiyar B, 1st United States Volunteer Cavalry Regiment. A lokacin da
Yaƙin San Juan Heights, Rynning ya jagoranci jagorancin Amurka bayan mutuwar Kyaftin Buckey O'Neill. Bayan 'yan mintoci kaɗan sai ya jagoranci Rough Riders zuwa Kettle Hill kuma shi ne Ba'amurke na farko da ya isa taron. A karkashin mummunar wuta daga kusa da San Huan Hill, Rynning ya umarci mutanensa su yi amfani da tutar rundunar don tara wasu kuma a wannan lokacin ne tutar ta yi mummunan rauni. A yanzu haka Ma'aikatar Laburare da Tarihi ce ke adana tutar a ginin babban birnin jihar a Phoenix, Arizona. Bayan haka, Rynning ya shiga Theodore Roosevelt a cikin cajin San Juan Hill, wanda ya ƙare yakin da nasarar Amurka.