Barry Goldwater? Leland Stanford? Mariano Vallejo? Sam Houston? Daniel Boone? David Crockett? Crazy Horse? Nathan B. Forrest? Tecumseh? Edward Teller? Bill Bridger? Jim Thorpe? et al....left out. I do not see how persons such as Betty Friedan, Earl Warren, Rachel Carson, William Lloyd Garrison or George Gallup could top these.
I might not be American, but I do know this.
If george washington isn't the greatest American, nobody is.
Without a doubt, Goldwater was the most influential politician of the 1960s, and one of the most influential of the 20th Century. While he lost in a landslide, his influence some 40 years later is much greater than that of the one who beat him in 1964. What other "loser" of a presidential election can make that claim.