Not necessarily ASB but difficult.
The three most important questions are
1 ) Is the Axis the same as OTL (Nazi Germany, Fascist Italy, Imperial Japan under Tojo) ?
2 ) Are the USA an active member of Axis ? Or an Axis-leaning neutral like Francoist Spain ? The first option is harder.
3 ) Why do the USA join (or support) Axis ? Japanese ambitions to dominate China were a threat to US interests (and the primary motive of the war for Japan was always China). So a compromise has to be reached there.
Then, the USA didn't like the idea of one empire dominating continental Europe (and possibly parts of Africa and Near East), and wanted to maintain Britain (important ally and trade partner) safe.
Finally the USA would remain a democracy (no way Long manages to pull a stable dictatorship) with large segments of population either Anglophile or isolationist. And even US far right placed US national interest above foreign allies.
So you need good and strong reasons to align with the Axis (likely including Red Scare and anticommunism, but not just that), as well as a reasonable compromise between US interests and Japanese/German aims (in Far East and Western Europe).
Possible but not easy.