Many decisions taken in legislatures or committees are subject to lobbying efforts. A seminal contribution to the literature on vote-buying is the legislative-lobbying model pioneered by Groseclose and Snyder (1996), which predicts that lobbies will optimally form supermajorities in many cases. Providing the first empirical assessment of this prominent model, we test its central predictions in the laboratory. While the model assumes sequential moves, we relax this assumption in additional treatments with simultaneous moves. We find that lobbies buy supermajorities as predicted by the theory. Our results also provide supporting evidence for most comparative statics predictions of the legislative lobbying model with respect to legislators' preferences and the lobbies' willingness-to-pay. Many of these results carry over to the simultaneous-move set-up but the predictive power of the model declines.

立法机关或委员会做出的许多决定都需要游说努力。由Groseclose和Snyder（1996）率先提出的立法游说模型是有关购买投票的开创性文献，该模型预测说，在许多情况下，游说者将以最佳方式形成多数。提供此突出模型的首次实证评估，我们在实验室中测试了其中心预测。当模型假设连续移动时，我们在同时移动的其他处理中放宽了此假设。我们发现，游说者购买了该理论所预测的多数。我们的研究结果还为立法游说模型的大多数比较静态预测提供了支持性证据，这些预测涉及立法者的偏好和游说者的支付意愿。