Please Explain

Alright so we are told that the public in the U.S. has previously been conditioned to support a SUBSTANTIAL defense budget by the threat of confrontation with the Eastern bloc. But, we are told that now not only is the threat dissolving, but the Eastern bloc is, as well. So, the argument concludes from this that it is unlikely whether the public can be persuaded to support an ADEQUATE defense budget. Well, we knew that when there was a threat, the public could be depended on to support a SUBSTANTIAL defense budget, but now that the threat is dissolving, the public will probably not support an ADEQUATE budget. Well, how do we know that a "substantial" budget is the same as an "adequate" budget? We have no information telling us that those are the same amounts. What if an "adequate" budget is a much smaller budget than a "substantial" budget? In that case, the public could still be relied upon to support the "adequate" budget after the threat is gone since even though the threat has dissipated, the "adequate" budget is much smaller than the "substantial" budget. Answer choice (E) states: "It hinges on the term 'adequate,' the precise meaning of which requires reevaluation in the new context." This is precisely what answer choice (E) is pointing out. The term "adequate" is key in evaluating the argument. Hope that clears things up! Please let us know if you have any other questions.