Washington (CNN) -- "I'm going to appoint Thurgood Marshall to the (Supreme) Court." This monumental, unexpected bombshell from President Lyndon Johnson -- spoken in private in the summer of 1965 -- set in motion a history-making drama, revealed for the first time in newly public audio tapes. In secret recordings and transcripts made exclusive to CNN, Johnson laid out a politically crafty plan that was years in the making to groom Marshall as the first African-American on the high court. It was part of a broader White House strategy to implement the president's civil rights agenda, something he openly hoped would cement his legacy and strengthen the Democrats' base.
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Secret tapes of President Lyndon Johnson released exclusively to CNN
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Tapes reveal president's long-term aspirations for Thurgood Marshall
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Johnson carefully laid out a path for Marshall to join Supreme Court, tapes show
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LBJ on Marshall: "I want to build him up where he's impenetrable"
Thurgood Marshall
Marshall
Thurgood Marshall
Marshall
Marshall
Leaving the security of a lifetime job on the bench for an uncertain political post -- where he could be fired at any time -- at first concerns @placeholder, who asks for a day or two to think about the offer.
Thurgood Marshall
Marshall
Thurgood Marshall
Marshall
Marshall
By the time of his government appointments, @placeholder was in his mid-50s and itching for new challenges.
Thurgood Marshall
Marshall
Thurgood Marshall
Marshall
Marshall
@placeholder is asked to suggest names of other black leaders suitable for top administration posts, including agency heads and ambassadorships.
Thurgood Marshall
Marshall
Thurgood Marshall
Marshall
Marshall
@placeholder, despite being among just a handful of top black officials in the administration, appears slightly uncomfortable seeming to speak for all African-Americans in a purely political context.
Lyndon Johnson
Johnson
Lyndon Johnson
Johnson
LBJ
I see that they say they're getting very disillusioned with @placeholder," says the president, referring to himself in the third person.
African-American
But it is clear from this conversation that LBJ is using Marshall's grooming for the Supreme Court as the model he will use to boost other outstanding @placeholder candidates to senior government positions.
Lyndon Johnson
Johnson
Lyndon Johnson
Johnson
LBJ
@placeholder replies in a sweet, soft voice, "Well, I know he'll be very worthy of it, and I know that both of us will be proud of him."