Read, read, and read some more:
http://www.google.com/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#q=containment%20policy%201946
What were the original goals and purposes of the containment policy in 1946?
How did the policy change its meaning over time?
2 answers
You could also try this link.
http://www.google.com/#q=containment+policy
http://www.google.com/#q=containment+policy