March 3, 2008: Long-Term Cycles in American National Electoral Politics Found to Occur More Rapidly Than Previously Believed APSA Press Release

For Immediate Release
Bahram Rajaee, (202) 483-2512

Long-Term Cycles in American National Electoral Politics Found to Occur More Rapidly Than Previously Believed

Are We Entering a New Period of Democratic Dominance? New Research Suggests Shifts in Party Control Over U.S. House, Senate, and Presidency Occur Roughly Every 14 Years.

Washington, DC—American electoral politics have been characterized by frequent and regular cycles of support for the Republican and Democratic parties. A new study has found that these cycles, and the shifts in party control that accompany them, occur more frequently than previously thought; it also presents a theoretical model for explaining them.

Conducted by Samuel Merrill, III, (Wilkes University), Bernard Grofman (University of California, Irvine), and Thomas Brunell (University of Texas at Dallas) the study is entitled “Cycles in American National Electoral Politics, 1854-2006: Statistical Evidence and an Explanatory Model,” and appears as a research article in the February issue of the American Political Science Review, a journal of the American Political Science Association (APSA).  The full article is available online at /imgtest/APSRFeb08Merriletal.pdf

Conventional wisdom among many observers of American politics has been that a regular and relatively sudden cycling of party dominance—known as “realignment”—occurs roughly every 30 years, although previous studies focus on different dimensions of this phenomenon and there has been more skepticism about the truth of this claim for the post WWII period. This new study emphasizes gradual shifts in Democratic versus Republican party dominance from 1856-2006 and explores related questions such as whether realignment cycles actually exist; if change is random or regular; whether the cycle interval is the same for the U.S. House, Senate, and Presidency; and whether observers can identify the forces that drive realignment cycles. 

The authors also develop a dynamic model that depends on the tensions between parties’ policy and office motivations and between voters’ tendency to sustain incumbents while reacting against extreme policies, to account for these cycles.  Their model utilizes the empirical work of James Stimson (University of North Carolina, Chapel Hill).

Their study is based on a statistical procedure known as spectral analysis and confirms the existence of cycles—defined as the duration of ascendancy by one party plus the duration of ascendancy by the other party. It also yields several notable findings that dramatically reduce the time horizon of our understanding of realignments. In the U.S., shifts in partisan control in both the House and the Senate were found to have occurred on average about every 14 years, with presidential shifts of control averaging about the same.  Thus, full cycles in all three bodies are completed about every 26-28 years—more rapidly than many scholars have previously thought, but close to the estimates of 30-year cycles suggested by Arthur Schlesinger, Jr. and Sr.

The predictive model developed in the study supports these findings and clarifies how the cycles for the House, Senate, and president track one another. “The substantive message…is that…the cycle lengths are approximately the same….[and that] the peaks and valleys of all three time series occur at approximately the same time,” observe the authors.

“…We emphasize the long-term and incremental ebb and fall of national party support patterns,” conclude the authors, noting that “our statistical evidence suggests a shorter cycle of rise and fall than was suggested by some earlier realignment theorists….”  Explaining the dynamics of American national politics is a long standing goal of observers and analysts and this new research helps achieve that goal by refining our long-term understanding of national electoral realignments.  In particular, the study emphasizes the impermanence of partisan dominance, suggesting that based on historical patterns the recent Republican ascendancy is likely soon to be replaced by Democratic ascendancy. 

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 The American Political Science Association (est. 1903) is the leading professional organization for the study of politics and has over 14,000 members in 80 countries. For more news and information about political science research visit the APSA media website,

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