Yes in key measurable ways (especially affective polarization and partisan sorting in the US since the mid-20th century), but not the worst in American history, and the picture is mixed depending on the metric and country.
What the Data Shows
•Affective polarization (dislike/distrust of the other side as people, not just disagreement on policy) has risen sharply. Pew Research and others document growing shares of Democrats and Republicans who view the opposing party as a threat to the country's well-being, immoral, or dishonest. Feeling thermometers (American National Election Studies) show the gap in warmth toward one's own party vs. the other has widened substantially since the 1980s–1990s. People are more likely to object to intermarriage across party lines and to sort socially.
•Ideological sorting and elite polarization: Parties are more internally homogeneous and farther apart. DW-NOMINATE scores (and similar measures) for Congress show the parties pulling apart since the 1970s, with vanishing overlap—far more than the mid-20th century era of conservative Democrats and liberal Republicans. Voters have sorted: liberals into Democrats, conservatives into Republicans. Issue differences on abortion, guns, race/immigration, and the role of government have grown on average, though not uniformly on every topic.
•Compared to the recent past (post-WWII to ~1990s): Clearly higher. The "end of ideology" / bipartisan consensus period featured more cross-cutting cleavages and legislative deal-making. Today's media environment (cable, internet, social media) and primary incentives amplify extremes and negative partisanship.
•Not unprecedented historically: The 1850s–Civil War era was vastly more polarized, with slavery, secession, and actual mass violence. The late 19th century (populism, labor conflict, sectional bitterness), the 1960s–1970s (riots, assassinations, Vietnam, campus unrest, Weather Underground-style violence), and parts of the early 20th century saw intense conflict, institutional strain, and higher political violence rates. Today's rhetoric is heated and trust in institutions is low, but homicide, riots, and armed conflict remain far below those peaks. "Worse than ever" claims usually ignore this.
Mass publics are still less polarized than activists, donors, and elected officials on many concrete issues; a sizable center exists but is less decisive. Asymmetric patterns appear in some data (e.g., faster leftward movement among Democrats/liberals on cultural/identity issues in recent decades; Republican shifts on trade/immigration/nationalism), but both sides have contributed to sorting and negative partisanship.
Drivers (Not Just "The Other Side")
•Geographic, educational, and social sorting + primary systems that reward base mobilization.
•Media fragmentation and incentives: outrage and identity content outperform nuance. Social media accelerates this without inventing it.
•Elite cues and institutional changes (weaker parties as gatekeepers, safer seats).
•Real value and demographic shifts: immigration, secularization, economic changes, and cultural revolutions create genuine, high-stakes disagreements rather than mere "misinformation."
Cross-nationally, similar rises appear in several Western countries with populist surges and cultural conflict, though US two-party dynamics and federalism shape it differently. Places with proportional systems or different histories show variation.
Caveats and Trade-offs
Polarization clarifies choices and can reflect sincere belief differences rather than pure irrationality. Low polarization can mean elite collusion or suppressed conflict (as in some one-party dominant eras). The bigger practical risks are eroded norms, reduced compromise capacity on must-pass items, and occasional violence or institutional hardball—not that democracy is collapsing tomorrow. Shared factual baselines have frayed, which is costly.
For primary sources, see Pew's long-term polarization reports, ANES feeling thermometers, DW-NOMINATE/Poole-Rosenthal data, and historical work by scholars such as Fiorina (on the limits of mass polarization), Abramowitz, or Levitsky/Ziblatt (more alarmist institutional takes). Trends can reverse with new coalitions or external shocks; they are not destiny.