Don’t forget that Teddy Roosevelt, former Republican president, formed a third party because the GOP wasn’t Progressive enough for him. Progressivism afflicted both parties then, and still does today.
TR was also a big eugenics advocate.
To be fair to the progressives/eugenicists of the early 20th Century, I don’t think they understood the horrors to which it would lead.
After the Nazi concentration camps were liberated by elements of the US Army, eugenics was pretty much discredited.
Margret Sanger’s people still want to abort black babies.