As far as I can see, there is very little to compare that situation and the Russian invasion of Ukraine.
No doubt some in the government wanted to attack, no different than you could find who want to attack Iran in today's government, but it's not the US government's position. FDR was definitely more interested in getting involved internationally, but the Republicans were staunchly isolationist.
The comparison to Russia and Ukraine is there. Russia preemptively attacked Ukraine because it wanted to prevent NATO from getting a foothold in it's sphere of influence. Japan considering the Pacific Ocean and namely the resources in South East Asian there's, so preemptively attacked the US to prevent it from opposing it's control over the Pacific.
They were except for their nominee running against FDR in 1940. His interventionist stance (and otherwise complete lack of political experience) made FDRs victory all but assured.
I’m not sure how you have a base so aligned on a topic that gives them an excellent chance on defeating the incumbent nominate a political nobody who holds a dissenting opinion. The same nobody who went on to serve in FDRs administration.