PHOENIX — Pew Research Center has been surveying registered voters for decades to ask if they consider themselves Republicans or Democrats.
In the late 90s, the gap between the two parties was narrow with Democrats having a slight advantage.
In 2003, Democrats took the lead and never relinquished it.
The gap spread to its widest in 2008 but narrowed to the parties running even in 2022. By the following year, Democrats had shifted a point ahead but it was the closest the parties have been before a presidential election year in two decades.
A major reason for the narrow gap is the trend of voters sorting into the two parties by large demographic cohorts like age, race, and education which has continued with little change in momentum.
Before 1999, there was little difference between the party preferences of voters by what decade they were born in. In the decade that followed, a pattern emerged in which older voters began identifying at higher rates as Republicans and younger voters as Democrats.
By 2023, the difference between voters born in the 1940s and those born in the 1990s preferred the opposing party by a twenty-point margin.
Another big trend reported by Pew is the sorting of voters by education and gender.
By gender alone men are more Republican by a six-point margin while women are seven points more Democratic.
In recent years, more than half of men with college degrees said they were Democrats while men without college degrees, already more Republican, now lean to the right by ten points.
For women, the effect is the opposite. The largest spread by gender and education belongs to women with college degrees who are twenty-three points more Democratic. Women who do not have a college degree historically have also leaned Democratic, according to Pew’s data, but since 2022 most of them now identify as Republican.
Pew also identified key demographic groups who identify most with either political party.
For Republicans, white evangelical protestants were the most loyal group. They make up 17% of registered voters and 85% of them identify as Republicans.
By contrast, the most loyal Democratic group was Black voters, who make up 11% of registered voters and 83% identify as Democrats.
