Material conditions will inevitably worsen as imperial super profits decrease and the bourgeoisie desperately try to hold on to their dominant position, looking to pillage whatever they still can. Crises will get worse and more frequent. The effects of climate change will be more apparent, massive disasters killing thousands in the US and even millions abroad in more vulnerable places. Economic disasters of a scale never seen before in history. Countless new wars, conflicts, and struggles, both home and abroad. Support will increase as it did with the Bolsheviks. The Bolsheviks had some ~10,000 at the start of 1917, by the end of the year they had half a million.
They’d be foolish to single out the PSL as that would only draw attention to them. Maybe they’ll decide they’re a wing of the nefarious ‘Antifa’ though