What is the fundamental difference between the view of ball and kennan?

The fundamental difference between the view of ball and kennan lies within whether United States should be or should not be involved in the vietnam war.
Ball supported United States' involvement because he believed it was a very important step to stop the spread of communism, while Kennan believed that we shouldn't be involved because it took too much of our resources.

Is there a passage that comes with this question or should i know this right off the bat, because if it is, i probably have short term memory loss or college is too stressful

Where are the following ?