Question 1
Answer: E
The author's main argument here is that the commitment trap was the main reason for full-scale US intervention in Vietnam in 1965. The author explains that the commitment trap is like a ball rolling towards an inevitable conclusion. Therefore, the person who is ultimately to blame for the war (according to the author) would be the person responsible for setting the ball rolling in the first place.
The first President we're told about who got the US involved in the Indochina region was President Truman, during the time of French occupation. According to the argument, this triggered a chain of events where later Presidents were forced to escalate incrementally. Therefore, although the author does not tell us explicitly that Truman was ultimately to blame, we can extrapolate this from the text.
Therefore, E is the correct answer.
Question 2
Answer: D
The difficulty here is that all of these seem to be true, for instance the author uses inverted commas and sarcasm to tell us that the non-combatant advisors were probably used in conflict (B), and reminds us of the "disastrous" division of Korea, which foreshadows events in Vietnam (A).
The trick is to decide which 4 assumptions are unstated and which is stated the most explicitly. The answer is D: had Kennedy truly wanted to escalate, he would have initiated full intervention and not his tokenistic gestures. The author clearly states the following:
"he did not engage in full-scale war. Rather, he presided over more tokenistic escalation"
"This was clearly not the decisive military intervention of a President that truly wanted to escalate, but a President forced to do something"
Question 3
Answer: B
We are looking for the statement which most successfully undermines the evidential basis of the commitment trap, or provides an argument whose factor is more dominant than the author's.
A: This is paraphrasing the commitment trap. "Wars have an uncontrollable direction of their own" is the same as the metaphor about a ball rolling to an inevitable conclusion.
C: The US was already involved in the region prior to the French defeat, so there must be a more important factor in determining why this occurred in the first place.
D: Political expectation is merely a factor in the commitment trap which forces Presidents to act as they do
E: We are told that a failure to hold the elections merely "solidified the inevitability" - it did not create the inevitability in the first place.
B is the correct answer as it provides a persuasive alternative for the the cause of intervention. That is, the reason Truman got involved in the first place was a desire to tackle communism.