A reason that the United States and its allies formed NATO was to invade the Soviet Union.
establish a single government in Europe.
defend member nations against Communist attacks.
promote free trade among its members.

C )  defend member nations against Communist attacks.

Explanation:

It is the correct answer trust me.

`stare decisis is a legal doctrine that obligates courts to follow historical cases when making a ruling on a similar current or future case. stare decisis ensures that cases with identical facts be approached in the same way, unless overruled by the same court or a higher court such as the us supreme court. simply put, it binds courts to follow legal precedents set by previous decisions.

stare decisis is a latin term meaning "to stand by that which is decided".