We explore the role of "political discontent" as a second dimension of American public opinion. Others have shown that a second dimension tends to capture social and/or racial attitudes. What happens when indicators of discontent are included in such analyses? Using data from two surveys and the ordered optimal classification (OOC) procedure, we scale seven items from the "discontent" literature alongside a larger set of questions that has been shown to capture the two-dimensional structure of mass opinion. Discontent items dominate the second dimension in both data sets. Further, five of the seven items predict voting for "insurgents" in the 2016 presidential primaries. Second-dimension attitudes matter in elections and concern the political system writ large. By extension, the liberal-conservative heuristic gives an incomplete picture of mass political behavior.