Although the scholarly literature on incumbency advantages focuses on personal advantages, the partisan incumbency advantage — the electoral benefit accruing to non-incumbent candidates by virtue of being from the incumbent party — is also an important electoral factor. Understanding this phenomenon is important for evaluating the role of parties vs. individuals in U.S. elections and the incentives of incumbents and their parties in the legislature, among other things. In this paper, we define the partisan incumbency advantage, explain its possible role in elections, and show how it confounds previous estimates of the personal incumbency advantage. We then exploit close elections in conjunction with term limits in U.S. state legislatures to separately estimate the personal and partisan incumbency advantages. The personal advantage is perhaps larger than previously thought, and the partisan advantage is indistinguishable from zero and possibly negative.