Shields were generally made of wood, covered with leather, or some similar substance. To secure them, in some sort, from being cut through by the sword, they were surrounded with a hoop of metal. ↗
There can be no equality or opportunity if men and women and children be not shielded in their lives from the consequences of great industrial and social processes which they cannot alter, control, or singly cope with. ↗
Parents, however old they and we may grow to be, serve among other things to shield us from a sense of our doom. As long as they are around, we can avoid the fact of our mortality; we can still be innocent children. ↗
So you're quite right that when... as the Cold War grew and expanded out of Europe, we ourselves had to take refuge behind the shield of the Monroe Doctrine. ↗
On Earth, we still have a beautiful atmosphere that precisely maintains a thermally driven climatic system that shelters, shields and sustains our natural treasures. ↗