Answer: It could end the risk of a missile attack.
Step-by-step explanation:
Let us look at the paragraph and see if we can pull details to answer this question.
In the paragraph, we see that Ronald Reagan says this will "begin to achieve our ultimate goal of eliminating the threat posed by strategic nuclear missiles" and that the "only purpose – one all people share – is to search for ways to reduce the danger of nuclear war" (Ronald Reagan).
These pieces of evidence lead us to the conclusion that the answer is:
It could end the risk of a missile attack.