Substantial constituency influence over the lower house of Congress is commonly thought to be both a normative principle and a factual truth of American government. From their draft constitution we may assume the Founding Fathers expected it, and many political scientists feel, regretfully, that the Framers' wish has come all too true. Nevertheless, much of the evidence of constituency control rests on inference. The fact that our House of Representatives, especially by comparison with the House of Commons, has irregular party voting does not of itself indicate that Congressmen deviate from party in response to local pressure. And even more, the fact that many Congressmenfeelpressure from home does not of itself establish that the local constituency is performing any of the acts that a reasonable definition of control would imply.