In U.S. Politics, Party Rule Flips Like Clockwork

March 13, 2008 -- Democrats, take heart. The latest Republican ascendancy, which began when the party took over the U.S. House of Representatives in 1994, may be coming to an end -- according to new research in the field of political science.

If history is any judge, party power in American politics seems to switch back and forth at consistent, predictable intervals.

A team of three researchers looked at every election since 1854 and tallied the percentage of seats in the House and Senate won by each party.

To find patterns in this data, Samuel Merrill III, a mathematician at Wilkes University in Wilkes-Barre, Penn., borrowed a tool from astronomers: spectral analysis, a statistical method usually used to find repeating cycles in sunspots.

The tool uncovered a rhythm hidden within the Congressional election data, published in the February issue of the American Political Science Review. Every 12 to 15 years, party dominance seemed to swing from the Democrats the Republicans (or vice versa).

To explain this wobble in voter allegiance, Bernard Grofman, a professor of political science at University of California in Irvine, searched for spring-like forces that might cause such a steady oscillation.

Previous research has shown that voters like familiar faces; incumbent candidates typically pull constituents toward their party of choice. But voters also drift away over time, put off by the failed policies of those in power, wanting change.