Brits-Gone Draka could do the trick in 1900-1910.
I know your OP is trying to reverse the players and effects of WWI and WWII on the US and maybe other players.
Wars are tough to take out of historical context. I believe anything's possible, just differing degrees of likelihood.
WWI's bitter stalemate disillusioned the survivors about the glory of war, fighting for democracy, honor, etc. The European players suffered horrendous casualties and economic collapse afterward, which the ruinous mercantile policies pursued to pay off debts exacerbated. America found itself feeling a little foolish to be involved and vowed not to be sucked in again.
The positive social effects from WWI as far as America was concerned were female suffrage, increasing industrial and agricultural production and trade links with the outside world to hustle it abroad before Smoot-Hawley tariffs spannered the works, and more focus on sanitation thanks to the Spanish flu. The Progressives were active on public health before WWI, but a nasty plague taking out healthy adults focuses attention in a way that "normal" juvenile and elder casualties didn't.
As to WWII now we see the Nazis as evil and they most certainly were, but they weren't sui generis. They adopted eugenics techniques from rationales quite in vogue in the US and UK from 1900 on. The British invented concentration camps during the Boer War and freely conscripted coolie labor to make their Empire work. That was considered quite normal behavior in every colonial empire. The Belgians took it to a truly obscene extent in the Congo, but I digress. Basically, it'd take the British becoming the Draka in 1900 to do so.
Having the US fight a protracted war where we needed every willing body on the line and bit of talent to be cultivated to defeat whatever threatened America, whatever the skin tone, would allow whites to feel that the black/Hispanic/First Nation soldiers/sailors/marines/airmen had earned their citizenship and could finally be treated with respect and getting the GI Bill in 1915 or 1920.
(It'd take a looong time for the US to defeat the British Empire in 1900 with lots of foreign help. I'm thinking an ASB coalition of say, Germany and Russia at least, with Brazil, Venezuela, Holland, Austria-Hungary, Ottomans and China optional but welcome to keep the British and French dashing to and fro to defend their colonies. US builds up a navy that can be competitive with RN strength in one or two places and shred their trade routes. I'm assuming Japan is a British ally so they make a lot of hay in the Pacific using British bases before ASBC squadrons run them and the British fleet to ground after several nasty battles requiring considerable coordination with aircraft and subs using radio.
Just for giggles imagine Australians being eternally grateful to the Japanese for saving them from American invasion as a consequence of the Long War!
Bonuses from the Long War- China unites and extraterritoriality voided, India's free in 1910 or earlier, colonialism dies a much earlier death (the ASBC had to promise freedom to the African and Asian colonies' for them to revolt), a globally-integrated economy and polity comes about much sooner because it'd take a truly global effort to defeat the British Empire.
Racism in America dies a lot harder as America had to fight with folks of every color for freedom against Brits-and-French-gone-mad.
More madness upon request.