@nbcnightlynews: It was a stunning moment for U.S. foreign policy as President Trump seemingly committed the U.S. to owning the redevelopment of Gaza and potentially sending American troops to occupy the heavily disputed territory. Now the administration is walking back some of those comments. Kelly O'Donnell looks at what may be bluster and what may be U.S. policy, while Richard Engel reports on the shock rippling through the Middle East and world.