Speaker Billy McCoy routinely reminds members that the Rules Committee is the most powerful standing committee of the House of Representatives. That certainly is true in theory, and sometimes even in practice.
Ten members of the Rules Committee are elected by their own colleagues, voting in caucus by Congressional district at the beginning of every four year term. An additional member is appointed by the Speaker, who also names from the committee membership a chairman and vice chairman. The Speaker and the Speaker Pro Tempore also serve as committee members, attending and voting whenever they deem it necessary.
Of the ten elected members of Rules for the current term, five are Republicans, and five are Democrats. This is as close to parity as the GOP enjoys in any House committee. Nevertheless, when all members (elected, appointed, and ex officio) are in attendance, Republicans are outnumbered eight to five.