Article 1, Section 8:
The Congress shall have Power To lay and collect Taxes, Duties, Imposts and Excises, to pay the Debts and provide for the common Defence and general Welfare of the United States; but all Duties, Imposts and Excises shall be uniform throughout the United States;
If the Sec State can levy or forgive taxes, I can’t find it.
(not directed at you SES...just general frustration)
Understand, but this is a case of Treaty enforcement, 'Foreign Domain', 'Sovereign Immunity' and 'Diplomatic Immunity', that are traditional 'State Department' areas.
Basically, all Foreign Government-owned facilities used for diplomacy (here we are talking about UN operations in New York) are considered as their own governmental property and immune from local taxation. Various bilateral and multilateral treaties between the US and others make exceptions and additions.
Since this is governed by Treaty and the "Treaty Clause" Article II.2.2 US Constitution and has been confirmed by the US Senate, it is the State Department's business and control. Confusing, yes, straight-forward, no! Hope that this 'reduces' your frustration /smile!