Party-based theories argue that leaders of the majority party use restrictive rules to increase that majority's influence over policy. However, informational theorists suggest that restrictive rules reduce information costs and encourage committee specialization. Using data on every bill on which the House Rules Committee placed a rule from the 94 th through 109 th Congresses, I test these explanations. Considering the use of restrictive rules, the evidence verifies some of the predictions of partisan theories, but unveils mixed support for informational theories. In addition, we learn that Democratic and Republican majorities differ with respect to the use of restrictive rules. The results indicate that Republican majorities behaved as more of a procedural cartel than their Democratic predecessors.During the 96th Congress, the House Rules Committee placed an open rule that allowed lengthy debate and unlimited amendments on H.R. 6418, which was incorporated into the Motor Carrier Act of 1980. This act deregulated interstate trucking in numerous ways. Belzer (2000, 29) comments that:The new rules allowed free entry into the market, eliminated indirect routings designed to protect carriers from competition, sharply limited collective rate-making (formerly encouraged by the Interstate Commerce Commission to stabilize rates), and allowed carriers to charge discriminatory prices (discount pricing to high-volume customers).