Food aid is piling up inside Gaza. Here's why it's not reaching those in need

More than a dozen empty flatbed trucks from Gaza rumble through the opening in the massive concrete wall that marks the border here. They park on the Israeli side and forklift drivers jump into action, loading huge sacks of flour, along with boxes of watermelons, mangoes, tomatoes and onions. Within 30 minutes, the trucks turn around and drive the short distance back into Gaza.

This scene plays out multiple times daily at Kerem Shalom, now the main artery supplying Gaza with food and medicine. All this activity raises hope that...