What Is Political Polarization?
What is political polarization?
Political polarization is the process by which political opinions and identities move toward opposing extremes and the space between them shrinks. Researchers separate ideological polarization, meaning distance between policy positions, from affective polarization, meaning hostility toward the other side. In the United States, the second has grown faster than the first.
- Ideological polarization measures distance between policy positions.
- Affective polarization measures dislike and distrust of the opposing party.
- Pew tracking shows the share viewing the other party as a threat to the nation more than doubled between the mid-1990s and 2022.
- PRRI found in 2019 that 45% of Democrats and 35% of Republicans would be unhappy if their child married across party lines.
- Polarization is different from fragmentation, which describes people operating from different factual baselines.
The two measures researchers use
Political polarization is not a single quantity. Ideological polarization tracks how far apart the parties are on policy: taxes, immigration, health care, and so on. Affective polarization tracks how people feel about the other side, usually through thermometer ratings, trust questions, and willingness to associate socially. The two can move independently. Two countries can hold similar policy gaps while differing sharply in how much citizens dislike each other. In the United States, policy sorting has increased, but the sharper change is in affect.
What the data shows in the United States
Pew Research Center tracking found that the share of Americans who view the opposing party as a threat to the nation more than doubled between the mid-1990s and 2022. The 2019 PRRI American Values Survey found that 45% of Democrats and 35% of Republicans said they would be unhappy if their child married someone from the other political party. Party identity now predicts a wider range of social behavior than it did a generation ago, including neighborhood preference, dating, and hiring judgments.
Polarization is not the same as fragmentation
Disagreement over what should be done is polarization. Disagreement over what happened is fragmentation. Fragmentation is the harder problem because it removes the shared factual ground on which a policy argument can be settled. Gallup measured public trust in mass media falling from roughly 68% in 1972 to 28% in 2025. When fewer people accept a common set of sources, competing accounts of the same event can persist indefinitely without any mechanism to resolve them.
Why the distinction matters
Treating polarization as a moral failure produces advice that does not work: be more civil, read more widely, try harder. Treating it as an outcome of measurable structural changes in media economics, regulation, and platform design produces a different set of questions. The useful question is not why people became worse but what changed in the systems that shape what information reaches them and what behavior gets rewarded.