Been Taken In Or Distracted By Silly (And Irrelevant) Assertions About The Legal Status Of The IRS? Don't be.
They're nonsense (and so is most everything else usually asserted along with them, regarding the IMF, the UN, the Queen of England etc.--those who have seen this stuff will know what I'm talking about...)
HERE'S A SAMPLING OF THE CURRENT CODE SECTIONS representing the statutory provisions by which the Internal Revenue Service is authorized and established (the statutes themselves will be found below):
26 U.S. Code § 7803 - Commissioner of Internal Revenue; other officials
(a) Commissioner of Internal Revenue
(A) In general
There shall be in the Department of the Treasury a Commissioner of Internal Revenue who shall be appointed by the President, by and with the advice and consent of the Senate. Such appointment shall be made from individuals who, among other qualifications, have a demonstrated ability in management.
(2) Duties The Commissioner shall have such duties and powers as the Secretary may prescribe, including the power to—
(A) administer, manage, conduct, direct, and supervise the execution and application of the internal revenue laws or related statutes and tax conventions to which the United States is a party; and
(b) Chief Counsel for the Internal Revenue Service
There shall be in the Department of the Treasury a Chief Counsel for the Internal Revenue Service who shall be appointed by the President, by and with the consent of the Senate.
The Chief Counsel shall be the chief law officer for the Internal Revenue Service and shall perform such duties as may be prescribed by the Secretary, including the duty—
(A) to be legal advisor to the Commissioner and the Commissioner’s officers and employees;
(B) to furnish legal opinions for the preparation and review of rulings and memoranda of technical advice;
(C) to prepare, review, and assist in the preparation of proposed legislation, treaties, regulations, and Executive orders relating to laws which affect the Internal Revenue Service;
(D) to represent the Commissioner in cases before the Tax Court; and
(E) to determine which civil actions should be litigated under the laws relating to the Internal Revenue Service and prepare recommendations for the Department of Justice regarding the commencement of such actions.
26 U.S. Code § 7804 - Other personnel
(a) Appointment and supervision
Unless otherwise prescribed by the Secretary, the Commissioner of Internal Revenue is authorized to employ such number of persons as the Commissioner deems proper for the administration and enforcement of the internal revenue laws, and the Commissioner shall issue all necessary directions, instructions, orders, and rules applicable to such persons.
(b) Posts of duty of employees in field service or traveling
Unless otherwise prescribed by the Secretary—
(1) Designation of post of duty
The Commissioner shall determine and designate the posts of duty of all such persons engaged in field work or traveling on official business outside of the District of Columbia.
(2) Detail of personnel from field service
The Commissioner may order any such person engaged in field work to duty in the District of Columbia, for such periods as the Commissioner may prescribe, and to any designated post of duty outside the District of Columbia upon the completion of such duty.
The legislation represented by the foregoing sections of Title 26, USC, most of which goes back well into the 19th century, can be seen here.
A lot of folks have been misled about IRS "agency" status by a misunderstanding of events in Diversified Metal Products, Inc. v. T-Bow Company Trust, et al.
In that case, the Dept. of Justice argued that the IRS is not an "agency of the United States Government". This declaration has been widely bruited about as supporting the absurd notion that the IRS doesn't really exist, or is only a part of the Puerto Rican bureaucracy, or is merely a private outfit based in Baltimore, or similar nonsense.
However, all that was actually meant by that declaration was that within the particular context of this case the IRS did not qualify as an "agency". This was due to the nature of the issue being litigated and that of the particular statutory authority being litigated (which contained a common "for purposes of this section" qualifier, along with a custom "agency of the United States means XXXX" definition).
The letter below, which is a response by the Department of Justice to a question by a Nevada attorney about that declaration in Diversified, explains this-- and that in most other statutory contexts the agency DOES qualify as an "agency" and is, in fact, a bureau of the Department of Treasury.
As is always true in the law, context dictates meaning:
That is, an agency is an agency, but if a particular statute has a custom definition of the term "agency" for purposes of its own special and limited context, not everything which generically IS an agency may qualify as meeting that special, limited-application definition for purposes of that statute.
(And frankly, think about it. How credible is the proposition that Congress is incapable of providing the Department of Treasury, or the United States governmental structure generally, with an accounting and collections agency such as the IRS? After all, that IS what this ridiculous notion suggests in questioning the existence or status of everyone's least-favorite agency...)
Click here for an excellent history of the agency up until the mid 1940s.
Also, see the following. The portion chosen for underlining suggests that the person who secured it didn't really read what followed, but you should...