The US government under Roosevelt was opposed to the Nazis from the start, before WW2 began, on account of its fascist character.

While America was deeply racist at the time, it was also very unevenly racist, and even prominent Nazi fellow-travelers like Charles Lindbergh expressed revulsion at the level of Nazi racism displayed.

The genocide proper didn't begin until WW2, and by the time we were already, for all practical purposes, 'in the game', so to speak.

That's a complicated question without a clear answer. It's hard to establish the motivations of an individual person, but much harder when you're talking about the entire country. Generally, people were united in the war effort, but for a variety of reasons. The NYT downplayed the Holocaust and specifically tried to avoid focusing on antisemitism, in part because they were worried that people wouldn't like the idea of fighting a war to protect Jewish people, as racism and antisemitism were very much present. On the other hand, you had people like folk singer Woody Guthrie who explicitly connected the war to anti-fascism in his songs. But there were also plenty of people and media who had been praising Hitler, before he started invading everywhere.

Basically there were lots of reasons for lots of people to dislike the Nazis, so it's kind of hard to detangle who was motivated by what and to what degree. Generally though, if they had kept to their own borders, it's unlikely that any other country would have invaded them just for being fascists, and many countries went through great lengths not to go to war with them, because nobody wanted to recreate the devastation of WWI. Even then the US wasn't willing to get directly involved until it was directly attacked.

Uhh…yes, because yes. They didn’t just burst onto the scene after Kristallnacht but once the regular folk see the pogroms it’s suddenly a war crime

If you grab a book on Henry ford and his ilk then you’ll need a book on Reconstruction and then a book on plantations, etc. This is a country by and for land owning white men so there was a lot of stern words before the Infamous day, after that it was a mix of actual Steve Rogers and the same robber barons getting richer but we mostly agreed with the Reich until it hit our shores.

If Japan stuck to their close neighbors and ze Germans just annexed Western Europe…we probably wouldn’t have all the beach landings and such, see again Ford and his friend list.

Because they attacked, I am fairly certain.

Read Eisenhowers D-Day remarks. Most Americans believed the Nazis were a genuinely dangerous, oppressive evil that, left unchecked, were likely to subjugate the whole of Europe. Both their ideology and methods had to be rebuked on a moral level.

Because you got invaded. Nothing else.

Churchill (part American) always thought the Americans would join the war but they didn't.

Germany was getting held up in Russia and Japan attacked America. Hitler thought if he declared war on America then Japan would declare war on Russia. Hitler was more worried about Russia so it was a good trade. Unfortunately for him Japan kept they pact of non aggression with Russia so it just caused him another enemy.

It would be too simple to say either. Societies are diverse with multiple viewpoints.

Both. The autocratic bend that was already known of provided plenty of fuel for the pro-war camp, and it was a lot of what motivated Roosevelt to want to back the Allies as much as he was legally allowed.

Pearl Harbor was a tragedy, but as Churchill is attributed to have said, never let a good crisis go to waste.

Japan basically provided all the excuse the pro war camp needed to leeroy jenkins themselves at Hitler's face.

We built the bomb with the intention of using them on Germany, that is the kind of axe you've got to grind with someone who you hate for a lot more reasons than just that they socked your best mate.