So you want segregation and discriminatory racial laws back? I will give that LBJ made a mess of Vietnam like Kennedy. though.
Kennedy never 'backed down to the Soviets', he after all waged war in Vietnam, and carried out the Bay of Pigs invasion against Castro. So kind of a mute point.
The Soviet Union put the missiles in Cuba without the knowledge of the US military to begin with, so it isn't as if it was his fault for Soviet deception. In actuality the US traded old missiles in Turkey for Soviet missiles out of Cuba, and that's what ended the missile crisis. The US got more out of it than the Soviets, and it was in fact the Soviets that backed down in private discussions with Kennedy's administration.