The limits of the House Judiciary Committee are contained in the rules for the House of Representatives, of which, the relevant parts are shown below. Specifically, Congressional oversight is never limited by law, statute, or regulation; or, for that matter, the Constitution; that is to say, oversight, in and of itself, is unrestricted, as it applies to current law. Certain inquiries are restricted.
Broad as the power of inquiry is, it is not unlimited. The power of investigation may properly be employed only in aid of the legislative function. Its outermost boundaries are marked, then, by the outermost boundaries of the power to legislate. (Constitution Annotated)
The House Judiciary Committee is authorized to conduct oversight of "[a]dministrative practice and procedure" "[i]n order to determine whether laws and programs addressing subjects within the jurisdiction of a committee are being implemented and carried out in accordance with the intent of Congress ...".
While the committee is not "abusing" its oversight authority, some members of the committee may be "abusing" the process by making (or attempting to make) "political points" in their questioning of the Attorney General (AG). However, such "abuse" is Constitutionally protected in Article I, Section 5, "Each House may determine the Rules of its Proceedings, punish its Members for disorderly Behaviour, and, with the Concurrence of two thirds, expel a Member"; and by Article I, Section 6, "They shall in all Cases, except Treason, Felony and Breach of the Peace, be privileged from Arrest during their Attendance at the Session of their respective Houses, and in going to and returning from the same; and for any Speech or Debate in either House, they shall not be questioned in any other Place." (Embolding added.)
Without getting into the partisan motivations behind this, are there any recognized checks and balances under the separation of powers to stop congress exceeding its authority (to write legislation and set the budget) by confusing oversight with prosecutorial and judicial inquiry?
No, in practice, the House Judiciary Committee normally conducts the quasi-judicial inquiries for the impeachment process; and, if one accepts Speaker Pelosi's arguments, the House Judiciary Committee could be, for all we know, conducting an impeachment inquiry of AG Barr.
Rules of the House of Representatives
Organization of Committees
Committees and their legislative jurisdictions
- There shall be in the House the following standing committees, each of which shall have the jurisdiction and related functions assigned by this clause and clauses 2, 3, and 4. All bills, resolutions, and other matters relating to subjects within the jurisdiction of the standing committees listed in this clause shall be referred to those committees, in accordance with clause 2 of rule XII, as follows:
(l) Committee on the Judiciary.
(2) Administrative practice and procedure.
General oversight responsibilities
(a) The various standing committees shall have general oversight responsibilities as provided in paragraph (b) in order to assist the House in—
(1) its analysis, appraisal, and evaluation of—
(A) the application, administration, execution, and effectiveness of Federal laws; and
(B) conditions and circumstances that may indicate the necessity or desirability of enacting new or additional legislation; and
(2) its formulation, consideration, and enactment of changes in Federal laws, and of such additional legislation as may be necessary or appropriate.
(1) In order to determine whether laws and programs addressing subjects within the jurisdiction of a committee are being implemented and carried out in accordance with the intent of Congress and whether they should be continued, curtailed, or eliminated, each standing committee (other than the Committee on Appropriations) shall review and study on a continuing basis—
(A) the application, administration, execution, and effectiveness of laws and programs addressing subjects within its jurisdiction;