Literally just has to stop funding to Israel wherever he’s able, whether it’s using his veto or directing the State Department to delay aid or make disbursement more difficult. He needs to publically condem the genocide like every sane person with two eyes has been able to do for months. No more blocking UN resolutions, no more calling student protestors antisemitic, veto the The Antisemitism Awareness Act etc.
He needs to do what people have been demanding since the very start of the genocide. Do what people were saying when they voted Uncommitted, what students are saying when they protest; stop giving Israel a blank check, stop pretending to criticize them"behind closed doors", stop funding genocide and carrying water for a fascist right-wing government.
He needs to do it now, the longer he delays the more people die, the less likely he is to get people to vote for him.