Answer:
The letter was calm and restrained.
Explanation:
Tension between the United States and Russia, formerly known as the Union of Soviet Socialists States were on the rise. From the rocket race, to the missiles race, the tensions between the two countries kept escalating. In the wake of the events, one of the potentially dangerous events was the Cuban missile crisis. Russia thought to build a missile base in Cuba. This would present a great danger to the US. In the letter, Kennedy is tentative in his approach. He exercises restraint. In fact, in one of the lines he says, "...I recognize Mr. Chairman, that it was not I who issued the first challenge in this case..." The president distances himself from the provocations that had been sent his his predecessors.
Basically an upgrade from your old position
One could be taking up for the other and get involved
