Whilst re-reading Roth's alternative history, The Plot Against America, I was reminded of Wendell Willkie (1892 - 1944), another outsider candidate who managed to get the Republican nomination for the 1940 election, despite being a Democrat less than a year previously.
He was for desegregation, the idea that became the UN, supporting the UK against Germany, education and healthcare.
He was a lone wolf, maverick type who was Roosevelt's personal contact with the Allies, who traveled across the globe meeting Churchill, Stalin, De Gaulle and others.
He represented William Schneiderman, a naturalised American who was stripped of his nationality due to not declaring that he was once a Communist. The Supreme Court supported Schneiderman and his citizenship was restored.
And he was very popular for doing so.
Willkie was the last Lincoln Republican and if honest Abe could see his party now he was be aghast - he would likely feel the same about the Democrats too - but he would be appalled.