Answer: The term "brutally frank demonstration" in this context refers to a clear and forceful expression of the United States' position on a particular issue. In this case, it seems to suggest that the United States needed to make a strong and unambiguous statement to demonstrate its commitment to its allies and deter its enemies. The use of the word "brutally" suggests that this demonstration would be direct and uncompromising, possibly even confrontational or aggressive. The overall message conveyed by this phrase is that the United States needed to be very clear about its intentions and capabilities in order to achieve its diplomatic objectives.