Legislative term limits adopted in the 1990s are in effect in fifteen states today. This reform is arguably the most significant institutional change in American government of recent decades. Most of the legislatures in these fifteen states have experienced a complete turnover of their membership; hundreds of experienced lawmakers have become ineligible for reelection, and their replacements must learn and perform their jobs in as few as six years.

Now that term limits have been in effect long enough for both their electoral and institutional effects to become apparent, their...