Not everyone agrees with Robert Caro's lionization of Coke Stevenson:
"It is daring of Caro even to mention Stevenson again after his "legend" was demolished by Sidney Blumenthal in a review of
Means of Ascent in
The New Republic of June 4, 1990. Blumenthal, who had done his homework, revealed that the saintly Stevenson had for years been plagued by accusations of taking money for phony oil leases; had won election as lieutenant governor in 1938 with the help of an endorsement from the reactionary governor "Pappy" O'Daniel, who is generally believed to have stolen the 1941 Senate election from Johnson; and was himself accused of stealing votes in the 1948 election. Indeed, charges of ballot-box manipulation by both sides in 1948 were so widespread that it is impossible to be sure who won the election.
"In the unkindest cut of all Blumenthal also revealed Stevenson's racism, support for segregation, and refusal in 1942, when he was the governor of Texas, to prosecute a group of good ol' boys who had dragged a black man from his hospital bed and lynched him. Caro circumvents these revelations by suggesting that they are inconsequential, because "civil rights was not an issue in that campaign" that brought Johnson to the Senate. He then goes on to criticize Johnson for failing to support an anti-poll-tax bill during his run for the Senate in 1948. Blacks did not seem to hold this against him, however; as Caro admits, Johnson won a heavy majority among them."
https://www.theatlantic.com/magazine/archive/2002/07/fatal-attraction/302549/
LBJ was far from being a racial progressive when he was elected to the Senate in 1948; and even in 1957 the civil rights bill he got through the Senate was seriously watered down (though it still set a precedent that the Senate
could pass a civil rights bill, and one can argue that no bill that was
not watered down could have survived a filibuster). But it's hard not to think that Stevenson would have been worse.