What is John F. Kennedy's purpose in this excerpt from his inaugural address?

But neither can two great and powerful groups of nations take comfort from our present course—both sides overburdened by the cost of modern weapons, both rightly alarmed by the steady spread of the deadly atom, yet both racing to alter that uncertain balance of terror that stays the hand of mankind's final war.

So let us begin anew—remembering on both sides that civility is not a sign of weakness, and sincerity is always subject to proof. Let us never negotiate out of fear. But let us never fear to negotiate.

Let both sides explore what problems unite us instead of belaboring those problems which divide us.

Let both sides, for the first time, formulate serious and precise proposals for the inspection and control of arms—and bring the absolute power to destroy other nations under the absolute control of all nations.

Let both sides seek to invoke the wonders of science instead of its terrors. Together let us explore the stars, conquer the deserts, eradicate disease, tap the ocean depths, and encourage the arts and commerce.

Let both sides unite to heed in all corners of the earth the command of Isaiah—to "undo the heavy burdens ... and to let the oppressed go free."

a]to emphasize the financial burden of maintaining a nation's defense
b]to explain the need to solve social problems that plague the world
c]to urge nations to make peace instead of war
d]to clarify the government’s stance on nations posing a threat to peace

John F. Kennedy’s purpose of this excerpt is to clarify the government’s stance on nations posing a threat to peace. We can determine the purpose of the excerpt by looking at the topic of the each paragraph. It is important to note that Kennedy employs the literary device of repetition as we can see with in the first words of sentences is the repetitive use of “let both sides.” The specific type of repetition here is known as anaphora, which is the repetition of a word (or in this case words) at the beginning of line/verse/sentence. That said, repetition is quite the effective literary device when the desired effect is to emphasize in order to highlight importance. And, what is being stressed when looking at the topics of each paragraph is the cumulative theme of the United States government’s stance on nations posing a threat to peace.