Parliamentarian of the United States House of Representatives
The parliamentarian of the United States House of Representatives manages, supervises, and administers the Office of the Parliamentarian, which is responsible for advising the House's presiding officers, members, and staff on procedural questions under the U.S. Constitution and House rules and precedents, as well as for preparing, compiling, and publishing the precedents of the House. == Role == The parliamentarian is appointed by the speaker of the United States House of Representatives without regard to political affiliation and solely on the basis of fitness to perform the duties of the position.
Source: Wikipedia — Parliamentarian of the United States House of Representatives (CC BY-SA 4.0)