Codifying Roe V Wade, passing the John Lewis VRA, replacing Alito/Thomas, and possibly Sotomayor, with progressives, ending trickle down economics, deregulation, and tax cuts for the 1%, continued support for Ukraine and NATO, and continued transition to renewable energy and limiting global warming to 1.5-2ºC. In addition, Trump not getting re-elected means Alito/Thomas/Sotomayor don’t get replaced with disgusting, and regressive Federalist freaks, and 1,000 of the other nightmarish policies the Heritage Foundation cooks up don’t get made law. Finally, ensuring that Trump doesn’t install himself or the theocratic/anarchocapitalist/autocratic/neonazi criminals he surrounds himself with into power permanently.
Anybody else can certainly chime in on something they feel like I missed.