Final answer:
The realignment of white Texans to the Republican Party was a multidecade process influenced by Southern Democrats' resistance to the A. Democratic Party's increasing focus on social issues and civil rights.
Step-by-step explanation:
According to Cal Jillson, the realignment of white Texans to the Republican Party was caused by a combination of factors that unfolded over several decades. Starting in the mid-20th century, rifts began to form within the Democratic Party as social issues, particularly those concerning civil rights, came to the forefront of national politics. Southern Democrats, who had traditionally given their support to the Democratic Party for economic interventions such as the New Deal, began to oppose the federal government's increasing role in advocating for racial integration. This led many to move away from their traditional party allegiance.
The transformation became evident in the 1960s and was significantly accelerated by the rise of the evangelical movement in the 1980 election, which saw many Southern Democrats switch their support to Ronald Reagan. This phenomenon, later known as the Reagan Revolution, consolidated a political shift where traditional Southern Democrats allied with pro-business Republicans, driven by their shared opposition to social welfare spending on civil rights and support for smaller government and states' rights.
It was not simply the Voting Rights Act of 1965 or desegregation that drove the shift but a broader discontent with the Democratic Party's social policies. This transition was part of an ongoing political realignment that also saw demographic shifts with Latino and Asian immigrants, most of whom favored the Democratic Party, changing the political landscape in Texas and the South.