“Time, Term Limits, and Turnover: Trends in Membership Stability in U.S. State Legislatures” by Gary F. Moncrief, Richard G. Niemi, and Lynda W. Powell, in Legislative Studies Quarterly (Aug. 2004), Comparative Legislative Research Center, 334 Schaeffer Hall, University of Iowa, Iowa City, Iowa 52242–1409.

More than a decade after the first term limits were imposed on state legislators, the results of the new policy are appearing, and they’re encouraging to its supporters. The turnover rate among legislators had been dropping, but term limit legislation has halted, and possibly reversed, that trend.

During the 1930s, more than half of all state legislators, on average, were replaced after every election. By the 1980s, that figure had dropped below a quarter: 24 percent in the lower houses and 22 percent in the upper houses, note political scientists Mon­crief, of Boise State University, and Niemi and Powell, both of the University of Rochester.

Starting in 1990, with Colorado, California, and Oklahoma, critics of the status quo in state government managed to impose term limits in 21 states. Legislators were restricted to terms of between six and 12 continuous years in one chamber. In three states, courts overturned the limits; in two, legislatures repealed them; in five, the laws haven’t been in effect long enough to have had a significant impact. That leaves 11 term-limited states driving the trend.

While the long decline in legislative turn­over continued into the 1990s in states without term limits, the turnover rate rose in the handful of term-limited states. Nearly 31 percent of lower-house legislators in those states were newcomers during the 1990s, compared with 25 percent during the 1980s. In the upper houses, turnover increased from 21 percent to 26 percent.

As Moncrief, Niemi, and Powell note, the rise in turnover rates wasn’t as predictable as it seems. Term limit laws might, for example, have discouraged individuals from challenging incumbents, and thereby actually decreased turnover.

Political scientists were right to predict that term limits would encourage more lower-house members to seek election to their state’s upper chamber. In states with term limits of six to eight years, about a quarter of the senators in 2002 were graduates of the lower house, compared with 10 percent in 1994.

Still to be answered, the authors note, is the key question about term limits: Does the frequent infusion of new blood improve the performance of legislatures more than the continual loss of legislative experience hurts it?