As conservatives began turning to the Republican Party in once strongly Democratic areas, Democratic voters in the state were largely based in the majority-Hispanic communities in Southern Texas and in populous metropolitan cities, such as Houston, Austin, San Antonio, and Dallas, as well as the heavily Hispanic city of El Paso on the state's western tip, which O'Rourke represented in the U.S. House.

Since 1990, Texas has voted for Republican statewide candidates in all elections, whether it be presidential, gubernatorial, or senatorial, often by large margins.

However, in 2016, Donald Trump defeated Democrat Hillary Clinton by only a 9-point margin, demonstrating a possible shift away from the Safe Republican status it had held for over a decade.

As of June 2018, Senator Cruz held a 49%–44% approval rating among Texans in a state Donald Trump won by 9 points against Hillary Clinton in 2016.

Among groups that tend to affiliate themselves more with the Democratic Party, Senator Cruz held a 29% approval rating among Hispanics, 37% among women, and 42% among college-educated voters.

Cruz won only one county that voted for Hillary Clinton in 2016, sparsely populated Kenedy (coastal region south of Corpus Christi).