Final answer:
President Kennedy proposed the Civil Rights Act of 1964, which President Johnson successfully passed through Congress.
Step-by-step explanation:
One of President Kennedy's proposed pieces of legislation that President Johnson successfully passed through Congress was the Civil Rights Act of 1964. This act aimed to end racial segregation in public places and prohibit discrimination based on race, color, religion, sex, or national origin. It was a significant milestone in the civil rights movement and marked a major step towards equality and justice.
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