Would Trump have sided with Hitler?Watch
Not that they didn't want to join the war on the side of the allies, just they lacked public support. Thus the best they could do early on was the lend lease programme. The whole pearl harbour issue partially sorted this out, but germany 'could' of stayed out of Japans war with the USA just like how Japan stayed out of Germany's war with the USSR.
Weirdly enough, nazi germany pressuring the Japanese to fight Russia over conquering china (which would still help japanese goals) would of probably meant the collapse of the USSR in my personal opinion.
I don't think he would do this out of ideological reasons, or out of the desire to save europe for the sake of europe.. but rather for the bennifit of america.
(its also worth noting that the Uk was the same.. we did not fight germany to end the holocaust and do defate nazism... we faught germany out of the interest of the UK and our allies/position in the world)