After ten years in the House, he seemed stuck in that position, which was for him was basically torture; not only was he not progressing towards the Presidency, he was also a political non-entity. LBJ entered a Senate race in Texas in 1948 in which it seemed he had no real chance of winning . . . so desperate was LBJ that he (and his powerful patrons) cheated before and after the election in terms of certain precincts and absentee ballots. His margin of victory was so slight, and so controversial, that his detractors referred to him as "Landslide Lyndon."
LBJ rose to power in the Senate with unprecedented speed. The Senate was just the right size for LBJ, in that he could make personal connections with the other 95 Senators. In 1955, LBJ became the youngest Senate Majority Leader in history, and soon after, he brought the Senate into the 20th Century, making it once again a relevant legislative body. LBJ's wife, Lady Bird, said that the 12 years that LBJ was in the Senate were the happiest of their lives. While he was very happy as Senate Majority Leader, he hadn't forgotten about his "Path to the Presidency"; in the 1956 Democratic National Convention, he refused to withdraw his name from consideration for the nomination.
Below: An absolute treat - a portion of Walter Cronkite's CBS coverage
of the Democratic National Convention
Through legislative miracle-making, LBJ was able to get the Civil Rights Bill of 1957 through the Senate (it became law soon after); however, it was mostly symbolic (and toothless), but it was the first such legislation in 82 years. LBJ figured that he would have an automatic Southern bloc of 352 delegates locked-and-loaded for the 1960 Democratic National Convention, which would put him over halfway to the nomination. LBJ didn't see any other formidable opponent in the Democratic Party that could deny him his coveted nomination for President. In LBJ's eyes, he was not only THE Senator, but he was THE Politician; in the late-1950s, he didn't think much of other Senators in terms of challenging him for the nomination, such as Stuart Symington, Hubert Humphrey, or John F. Kennedy.
LBJ's ascendency into politics occurred the moment his father's fortunes changed. In 1948, although he ran and won a U.S. Senate seat, LBJ vacillated before deciding to run; the fear of losing and being humiliated (like his father) almost trumped his desire to pursue his "Path to the Presidency." In 1958, with the stakes much greater, LBJ decided to play it close-to-the-vest heading to the 1960 Democratic National Convention; if events went his way, he wouldn't need to face an outright election until 8 November, 1960.
LBJ did enlist the man behind Truman's 1948 miracle campaign for advice, but he wound up ignoring that sage advice (e.g. organization, primaries, speeches, press conferences). In short, LBJ gambled that he would enter the 1960 Democratic National Convention with a strong plurality of delegates, and that none of the other challengers would even be close to his total. That, in turn, would lead to his mentor, House Speaker Sam Rayburn (at LBJ's left), and powerful established members of Congress that were loyal to him (or that owed him), working behind the scenes to deliver enough delegates to secure his nomination.
LBJ had badly miscalculated: Governors, not Representatives or Senators, were the key figures in delivering delegates for nomination at the national convention. Outside of Washington, D.C., most Americans didn't know, and couldn't care less, about Lyndon Johnson's impact as Senate Majority Leader.
LBJ still believed (it was remotely possible) that the first ballot at the Democratic National Convention in nominating a candidate for President would not produce an outright winner. Therefore, he believed, the Party Leaders would work behind the scenes on his behalf, and he would be nominated on the 2nd, 3rd, or at worst, the 4th ballot. But LBJ, this great "Reader of Men", had read one man entirely wrong . . . John F. Kennedy.