Why does the US keep blocking UNSC resolutions on Gaza?

The US has blocked yet another UN Security Council resolution calling for a ceasefire in Gaza and for Israel to lift all restrictions on the entry of humanitarian aid. Under the UN charter, the Security Council is responsible for maintaining international peace and security. It's made up of 15 members—10 elected and five permanent—who have the power to veto resolutions. This time, the 10 elected members supported the resolution. But Israel's biggest ally—the US—refused, saying it did not condemn Hamas. Does it mean the UN Security Council is unable to carry out its mandate?Become a supporter of this podcast: https://www.spreaker.com/podcast/the-truth--6487495/support.