Restrictive amendment rules, including closed and structured rules that only allow specified amendments, shot-up from around 30 percent of all rules in 1980 to 56 percent in the Democratic 103rd Congress (1993-94). The new Republican majority in the 104th Congress (1995-96) temporarily brought the percentage of restrictive rules down slightly to 42 percent.
Yet, the percentage of restrictive amendment rules edged-up again with each succeeding Congress, whether under Republican or Democratic control. In the Democratic 110th Congress (2007-08), it stood at 86 percent of all rules, and, by the Republican 113th Congress (2013-14), restrictive rules were 91 percent of the total.
Closed amendment rules alone accounted for 48 percent of the total in the last Congress — up from just 14 percent two decades ago, and 32 percent 10 years ago. Open amendment rules have almost gone the way of the dodo, with percentages hovering in the teens or lower.
One explanation for this ratcheting effect is offered by political scientists John E. Owens and J. Mark Wrighton in a 2008 study. They attribute it to increasing polarization in the House and an “emulation effect” (based on Daniel Patrick Moynihan’s “iron law of emulation”), positing that, “when one political party acquires a technique enhancing its power, the other party will likely adopt it as well in order to carry out election promises and to prevent potential dissidents from within its ranks from forming winning bipartisan coalitions with the minority.” This is especially evident when the two parties are in intense conflict and competition. House Republican leaders’ recent crackdown on GOP members who voted against the trade rule is one manifestation of this phenomenon.