If the tax imposed on the estate of the decedent under section 2001 is not finally determined before the taxable event, the amount of the tax imposed by paragraph (1) on such event shall be determined by using the highest rate of tax in effect under section 2001 as of the date of the decedent’s death.
No tax shall be imposed by paragraph (1)(A) on any distribution to the surviving spouse on account of hardship.
The estate tax imposed by paragraph (1)(A) shall be due and payable on the 15th day of the 4th month following the calendar year in which the taxable event occurs; except that the estate tax imposed by paragraph (1)(A) on distributions during the calendar year in which the surviving spouse dies shall be due and payable not later than the date on which the estate tax imposed by paragraph (1)(B) is due and payable.
If any property remaining in the qualified domestic trust on the date of the death of the surviving spouse is includible in the gross estate of such spouse for purposes of this chapter (or would be includible if such spouse were a citizen or resident of the United States), any benefit which is allowable (or would be allowable if such spouse were a citizen or resident of the United States) with respect to such property to the estate of such spouse under section 2014, 2032, 2032A, 2055, 2056, 2058, or 6166 shall be allowed for purposes of the tax imposed by paragraph (1)(B).
If the estate of the surviving spouse meets the requirements of section 303 with respect to any property described in subparagraph (A), for purposes of section 303, the tax imposed by paragraph (1)(B) with respect to such property shall be treated as a Federal estate tax payable with respect to the estate of the surviving spouse.
Any interest in a qualified domestic trust shall not be treated as failing to meet the requirements of paragraph (5) or (7) of section 2056(b) merely by reason of any provision of the trust instrument permitting the withholding from any distribution of an amount to pay the tax imposed by paragraph (1) on such distribution.
No tax shall be imposed by paragraph (1) on any distribution to the surviving spouse to the extent such distribution is to reimburse such surviving spouse for any tax imposed by subtitle A on any item of income of the trust to which such surviving spouse is not entitled under the terms of the trust.
Except as provided in regulations, the term “income” has the meaning given to such term by section 643(b).
An election under this section with respect to any trust shall be made by the executor on the return of the tax imposed by section 2001. Such an election, once made, shall be irrevocable. No election may be made under this section on any return if such return is filed more than one year after the time prescribed by law (including extensions) for filing such return.
The Secretary shall prescribe such regulations as may be necessary or appropriate to carry out the purposes of this section, including regulations under which there may be treated as a qualified domestic trust any annuity or other payment which is includible in the decedent’s gross estate and is by its terms payable for life or a term of years.