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Red and Blue States Explored

American Politics Have Become Polarized Into Red and Blue Since World War I

Lecture at 3 p.m. Monday, April 3, at UC Riverside will explore the issue

(March 30, 2006)

RIVERSIDE, Calif. ( — Only a decade ago, many Americans would have stared blankly when asked the meaning of so-called red and blue states, let alone what states were assigned to what color.

But the past two presidential elections have made the red-and-blue state discussion as much a part of the election-night news coverage as the popular vote itself. Today, more Americans use the shorthand of “red” Republican states or “blue” Democratic states.

So how important is the phenomenon of red-and-blue states in today’s American politics? Find out at 3 p.m. Monday, April 3, in a lecture open to the public in 2228 Sproul Hall. The UCR Statistical Consulting Collaboratory ( and the UCR Department of Political Science are co-sponsoring a presentation by UC San Diego professor Keith T. Poole called “Measuring the Ideology of Members of the U.S. Congress: 1789-2004.”

Using computer software to analyze roll-call votes in the U.S. Congress since 1789, Poole and colleagues have proven that political polarization has reached a divide in the U.S. not seen since before World War I.

Poole’s study provides a spatial map of Congressional roll call votes, allowing the us to visualize the political polarization of the legislature.

“Compared with 50 years ago, today’s legislature leaves little room for moderates,” said Antoine Yoshinaka, assistant professor of political science at UC Riverside.

“Poole's research allows the rest of the discipline to examine such questions, since he has estimated ideological ideal points of every member of Congress from the founding to the present,” Yoshinaka said. “What I find interesting in this research is that we can place the current environment in a larger context: Can polarization be explained by recurrent factors in American history, or is the current state of affairs a product of our time?”

Poole, along with Nolan McCarty and Howard Rosenthal, are authors of the new book Polarized America: The Dance of Ideology and Unequal Riches (MIT Press, spring 2006). He theorizes that race related issues, affirmative action, welfare, Medicaid and subsidized housing are all relevant factors in political polarization.

“Voting on race-related issues now largely takes place along the liberal-conservative dimension, and the old split in the Democratic Party between North and South has largely disappeared,” Poole writes.

The presentation is free, but parking on campus costs $6 per day.

The University of California, Riverside ( is a doctoral research university, a living laboratory for groundbreaking exploration of issues critical to Inland Southern California, the state and communities around the world. Reflecting California's diverse culture, UCR's enrollment has exceeded 21,000 students. The campus opened a medical school in 2013 and has reached the heart of the Coachella Valley by way of the UCR Palm Desert Center. The campus has an annual statewide economic impact of more than $1 billion.

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