Congressman Lyndon B. Johnson was officially declared to have defeated former Texas governor Coke R. Stevenson for the party's nomination by eighty-seven votes.

The validity of the runoff result was challenged before the U.S. Supreme Court due to allegations of irregularities, and in later years, testimony by the parties involved indicated that widespread fraud occurred and that friendly political machines[4] produced the votes needed for Johnson to defeat Stevenson.

[10] The dominant element in the Valley were Anglos (meaning white Texans since in Texas, the term did not necessarily imply English ancestry),[10] who tended to be ranch owners.

[15] Salas, a burly 6'1" (185 cm) man, known for his great physical strength, ferocious temper and love of violence, was in charge of elections in Precinct 13 in Jim Wells County.

[16] Parr was also a friend of Johnson, as Frank B. Lloyd, the District Attorney (DA) in Alice, Texas recalled: "George and Lyndon were very close.

[18] The commander of an Army Air Forces (AAF) training base in Laredo complained to Stevenson that half his men had been infected with venereal diseases after they visited brothels owned by Parr.

"[20] In Texas Democratic primaries, which were overseen by the party, not the state government, major candidates would "hold out" by delaying reporting their final tallies so they could add additional votes if needed.

[22]: 62–63  (Houston was in such poor physical condition that the trip to Washington to assume his duties taxed his health, and he died immediately before the special election.

[34] It was suggested to Johnson that he fly around in a helicopter owing to the size of Texas, and because many Texans lived in small towns where the roads were usually just mud tracks.

Johnson made campaign appearances around Texas six days a week from dawn to dusk and the spectacle drew large crowds to fairgrounds and other impromptu landing sites.

[44] Johnson made much of his brief World War II service, proudly wearing the Silver Star he had been awarded for heroism in 1942 (which later became the subject of controversy), and ridiculed Stevenson for not having military experience.

[46] One reporter who had apparently been misinformed by Johnson about his war record wrote about him: "...flying in B-29s, helping bomb one Japanese island after another into submission three years ago.

"[47] In addition, Johnson warned about the "red tide of Communism", predicting the Soviet Union would have an atomic bomb by 1951 and World War III might break out in the next decade, which he used as a way of contrasting his internationalism vs. the isolationism of Stevenson.

[55] By contrast, Stevenson's dignified behavior at the Texas Cowboy Reunion in early July, during which he led the participants' parade down the streets of Stamford on horseback, won him many cheers.

[68]: 600  On the other hand, Stevenson committed errors including appearing presumptuous by traveling to Washington to be photographed meeting with senior Truman administration officials and posing in the Senate chamber before the runoff had even taken place.

[69] The small counties of Hansford and Kinney, which had favored Stevenson with margins of over three to one and over two to one respectively in the primary, did not hold runoffs, assuming that their vote totals would not influence the outcome.

[68]: 605–606 In San Augustine and Shelby counties, abnormally large net vote gains for Johnson were later attributed to, "promises of contracts, loans and cash payments to individuals".

[77] In the runoff, Johnson's personal attention helped reverse the result, and the newly reported 2,000 vote margin in his favor made the contest competitive again.

[77] Early on Friday, September 3, an unusually late six days after the election,[26] new vote tallies from Jim Wells and Duval Counties were announced, replacing previous counts and giving Johnson the lead.

[80] In a subsequent radio address, Johnson claimed that he only learned of the vote totals on 31 August and challenged Stevenson to produce evidence of fraud.

[85] Stevenson went to Alice, the Jim Wells County seat, accompanied by Frank Hamer, a legendary Texas Ranger and longtime friend and hunting partner, and attempted to see the tally sheets.

[27]: 31:00 [86] Many feared a shootout as Stevenson and Hamer walked down the main street of Alice with their hands on their guns,[87] but they were able to avoid a confrontation by intimidating five of Parr's pistoleros into backing down.

[86] The bank manager allowed them to briefly view the list, then took it back when he saw them making notes, but Stevenson and Hamer had seen enough to convince them that blatant fraud had taken place, particularly in the vote totals for Precinct 13.

[99] In Means of Ascent, Robert Caro made the case that through the machinations of Parr and Salas, Johnson stole the election in Jim Wells County.

[100] At 9:50 pm on Friday, September 10, the Johnson team obtained an ex parte temporary restraining order to prevent a recount in Jim Wells County.

[101] At midnight on September 13, the Democratic Party's executive committee voted to certify Johnson's nomination by a majority of one (29–28),[101] with the last vote cast for Johnson by Temple, Texas newspaper publisher Frank W. Mayborn, whom John Connolly persuaded to cut short an out-of-state business trip and return to Texas to participate in the meeting.

[102] At 6:25 am on Wednesday, September 15, Stevenson obtained a temporary restraining order from federal District Court Judge Whitfield Davidson, who was vacationing at a cabin on Caddo Lake, which prevented certification of Johnson as the party's nominee.

[102] Fortas, an extremely adept lawyer known for his support for liberal causes, argued that a federal court had no jurisdiction over a state primary election.

[103] Associate Justice Hugo Black, sitting as a circuit court judge, ruled that jurisdiction over naming a nominee rested with the party, not the federal government.

In the 1950 United States Senate election in California, Democratic nominee Helen Gahagan Douglas, who was close to Johnson,[109] also employed one in her unsuccessful campaign against Richard Nixon.