Testing the Basis of Incumbency Advantage: Strategic Candidates and Term Limits in the California Legislature

Abstract

Conventional wisdom suggests that incumbent politicians use the resources of office to create an electoral advantage. But Cox and Katz (2002) argue that at least part of this incumbency advantage in the United States House of Representatives can be attributed to the strategic entry and exit decisions of incumbents. We test this claim by taking advantage of the natural experiment provided by state legislative term limits in California. By comparing different types of open seats, we identify the strategic component of the incumbency advantage that exists above and beyond the resource-based advantage. The vote loss suffered by the incumbent party is smaller in term-limited seats than in voluntary open seats, indicating that incumbents do sometimes leave when their electoral prospects look dim. Further evidence of this strategic component is that quality challengers run more often in voluntary open seats, while quality incumbent-party replacements run disproportionately in term-limited seats.