deductions or exclusions disallowed under section 911(d)(6) with respect to the amounts described in subparagraph (A). (3) Charitable trusts Subsection (a) shall not apply to a trust all the unexpired interests in which are devoted to one or more of the purposes described in section 170(c)(2)(B). (4) Not treated as tax imposed by this chapter for certain purposes The tax imposed under this section shall not be treated as tax imposed by this chapter for purposes of determining the amount of any credit under this chapter or for purposes of section 55. . (b) Clerical amendment The table of parts for subchapter A of chapter 1 of the Internal Revenue Code of 1986 is amended by adding at the end the following new item: Part VIII—Surcharge on high income individuals . (c) Section 15 not To apply The amendment made by subsection (a) shall not be treated as a change in a rate of tax for purposes of section 15 of the Internal Revenue Code of 1986. (d) Effective date The amendments made by this section shall apply to taxable years beginning after December 31, 2019.