Based on a previous thread I did about this the answer was that he'd be even more anti-Japanese early on and would probably take a similar set of actions as FDR did in 1939-40 with Germany. The real question is who would replace him and what would they do from 1941 on? Almost everyone, even the Republicans, wanted to aid Britain. Only Taft was for strict neutrality with a large US military buildup. Everyone else wanted to either do a version of LL or just grant the British billions of dollars. I don't think anyone on the political spectrum was for intervention in Europe, at least officially, before 1941. In Asia as I said Garner would likely push for some more aggressive actions against Japan, probably at the expense of the domestic agenda. Of course military build up to confront Japan would help the economy somewhat, so that may end up replacing some of the post-1937 public works programs.