This confusion mostly centers around the wording on the signs posted at the post office. The signs quote two sections of federal regulation - 18 USC 930 and 39 CFR 232.1.
Looking at 18 USC 930, it would appear, at first blush, that carrying firearms is prohibited. That section provides:
§ 930. Possession of firearms and dangerous weapons in Federal facilities
Release date: 2004-08-06
a. Except as provided in subsection (d), whoever knowingly possesses or causes to be present a firearm or other dangerous weapon in a Federal facility (other than a Federal court facility), or attempts to do so, shall be fined under this title or imprisoned not more than 1 year, or both.
So part of the confusion is rooted in the wording of this section. The prohibition applies to "Federal facilit(ies)" except as provide for in subsection (d). Subsection (d) provides:
(d) Subsection (a) shall not apply to-
(1) the lawful performance of official duties by an officer, agent, or employee of the United States, a State, or a political subdivision thereof, who is authorized by law to engage in or supervise the prevention, detection, investigation, or prosecution of any violation of law;
(2) the possession of a firearm or other dangerous weapon by a Federal official or a member of the Armed Forces if such possession is authorized by law; or
(3) the lawful carrying of firearms or other dangerous weapons in a Federal facility incident to hunting or other lawful purposes.
Many people have seized upon (d)(3) with the argument that they have a CHL, so their carrying of a firearm is an "other lawful purpose" and therefore they are exempt from the sign. This is problematic for several reasons. First, 39 USC 410 exempts Post Offices from 18 USC 930 (being a statute dealing with Federal facilities in general.) 39 USC 410, specifically dealing with post offices, states:
§ 410. Application of other laws
Release date: 2003-06-24
(a) Except as provided by subsection (b) of this section, and except as otherwise provided in this title or insofar as such laws remain in force as rules or regulations of the Postal Service, no Federal law dealing with public or Federal contracts, property, works, officers, employees, budgets, or funds, including the provisions of chapters 5 and 7 of title 5, shall apply to the exercise of the powers of the Postal Service.
(b) The following provisions shall apply to the Postal Service:
(1) section 552 (public information), section 552a (records about individuals), section 552b (open meetings), section 3102 (employment of personal assistants for blind, deaf, or otherwise handicapped employees), section 3110 (restrictions on employment of relatives), section 3333 and chapters 72 (antidiscrimination; right to petition Congress) and 73 (suitability, security, and conduct of employees), section 5520 (withholding city income or employment taxes), and section 5532 (dual pay) of title 5, except that no regulation issued under such chapters or section shall apply to the Postal Service unless expressly made applicable;
(2) all provisions of title 18 dealing with the Postal Service, the mails, and officers or employees of the Government of the United States;
Thus it would appear, by operation of 39 USC 410, that 18 USC 930, a law that deals generally with Federal property, does not apply to the Powers of the Postal Service. Rather, the only provisions of 18 USC that would apply are those specific to the post office e.g. Theft of Mail, Robbing Post Offices, Stealing Postal Money Orders etc. Further evidence of the proposition that 18 USC 930 does not apply to post offices is in the numbering of the aforementioned 39 CFR 232.1. As we will later examine, 39 CFR 232.1 clearly prohibits carrying firearms. CFR sections typically draw their numbering from the underlying laws that they are promulgated under, although there are numerous exceptions. The numbering of 39 CFR would be further evidence that 39 USC controls the situation, and not 18 USC.
The second problem with relying on 18 USC 930(d)(3) is that this section in no way EMPOWERS anyone to carry a gun; rather, that section simply states that 18 USC 930 does not apply to someone is lawfully carrying a gun incident to some lawful purpose. In Ohio's law, there is a big difference between something NOT BEING PROHIBITED and something BEING SPECIFICALLY LICENSED. Just because a statute says that certain conduct is not prohibited by that particular statute does not automatically equate into authority to engage in the conduct.
This is an important distinction, because the other part of the post office sign cites 39 CFR 232.1, which clearly does prohibit guns in post offices. In pertinent part, it states:
(l) Weapons and explosives. No person while on postal property may carry firearms, other dangerous or deadly weapons, or explosives, either openly or concealed, or store the same on postal property, except for official purposes.
The argument advanced against 39 CFR 232.1 is that a regulation cannot conflict with a statute, and indeed, a later portion, 39 CFR 232.1(p), states "Nothing contained in these rules and regulations shall be construed to abrogate any other Federal laws or regulations of any State and local laws and regulations applicable to any area in which the property is situated." So would 39 CFR 232.1 be in conflict if it is read to prohibit a CHL from carrying at the post office? It does not appear that this would be the case.
First, as we previously examined, 18 USC 930 does not apply to a post office. Second, as we previously examined, even if 18 USC 930 DID apply to post offices, remember that 18 USC 930(d) merely states that the lawful carrying of a firearm is not prohibited by 18 USC 930(a), not that the lawful carrying of a firearm is allowed. This being the case, what is 39 CFR 232.1 in conflict with? I think it is difficult to argue it is in conflict with anything.
This being the case, at a minimum, we have a situation where there is a valid RULE prohibiting the carrying of firearms, and properly posted signs evidencing this fact. That being the case, an Ohio CHL is prohibited from carrying at the post office by Ohio's criminal trespass. If an expansive reading is given to 39 CFR 232.1 and it is considered a FEDERAL LAW, and/or there is a federal law that makes it a crime to violate a provision of the CFR, then carrying at a post office would be prohibited by 2923.126(B)(10), meaning that the Ohio CHL would be committing a felony by carrying at the post office.
I do not want to be right about the answer to this question, because I personally see no problem with a CHL carrying in a post office. However, I think some of the information/discussion going on in forums has the potential to expose the Ohio CHL to a rude awakening.