Previous research identifies three variables that might bridge the inevitable conflict between the president and Congress: political party, political ideology, and presidential popularity. While the literature provides unambiguous evidence that party and ideology affect presidential support in Congress, the evidence that public approval affects support is mixed. The study reported in this article seeks to clarify the relationship using a research design that corrects some of the limitations of previous work. The analysis reveals that variables within Congress—party and ideology—have the strongest effect on presidential support. Although presidential popularity exerts statistically significant effects, the substantive effects are marginal. Public approval has slightly stronger effects on foreign-policy issues than on economic issues, and the effects are generally stronger on members of the president's party than on members of the opposition. The marginal effects do not increase in strength as we refine the measure of popularity to approach the relevant public for members of Congress.