I think this is exactly what the GP means when they discuss donating to political causes. If you can donate your $100 to buy a week's worth of food for a family in need, or donate it to a political campaign that credibly promises to end hunger in your country, it's not immediately obvious which is more effective (but the latter tends to be discounted by EA types, especially early in the history of the movement).

Perhaps the most effective altruism of all is that which makes Effective Altruism (TM) redundant.