Not American, but am anti-fascist so anyone is better than Trump. However it’s wrong to say that there is no other option.
The New Zealand Labour Party (centrist-left) won the election in 2017 by switching leaders much closer to election day:
On 1 August 2017, just seven weeks before the 2017 general election, Ardern assumed the position of leader of the Labour Party, and consequently became leader of the Opposition, following the resignation of Andrew Little. Little stood down due to the party's historically low polling.