Theories of representation suggest that candidates should respond ideologically to their constituency. Two-stage elections like those in the U.S. force candidates to decide which parts of their constituency they should respond to: citizens who are active enough to participate in primaries or those who only participate in general elections. We posit that non-incumbent candidates should mostly focus on the preferences of primary voters while incumbents should be largely unmoved by the preferences of either set of voters. We test these expectations using data from U.S. House and Senate contests and find support for our theory. Our results suggest that scholars should pay closer attention to the two-stage nature of U.S. elections when evaluating electoral responsiveness.