Unlimited Marital Deduction

§ 2056. Bequests, etc., to surviving spouse(a) Allowance of marital deductionFor purposes of the tax imposed by section 2001, the value of the taxable estate shall, except as limited by subsection (b), be determined by deducting from the value of the gross estate an amount equal to the value of any interest in property which passes or has passed from the decedent to his surviving spouse, but only to the extent that such interest is included in determining the value of the gross estate. (b) Limitation in the case of life estate or other terminable interest(1) General ruleWhere, on the lapse of time, on the occurrence of an event or contingency, or on the failure of an event or contingency to occur, an interest passing to the surviving spouse will terminate or fail, no deduction shall be allowed under this section with respect to such interest—(A) if an interest in such property passes or has passed (for less than an adequate and full consideration in money or money’s worth) from the decedent to any person other than such surviving spouse (or the estate of such spouse); and (B) if by reason of such passing such person (or his heirs or assigns) may possess or enjoy any part of such property after such termination or failure of the interest so passing to the surviving spouse; and no deduction shall be allowed with respect to such interest (even if such deduction is not disallowed under subparagraphs (A) and (B))— (C) if such interest is to be acquired for the surviving spouse, pursuant to directions of the decedent, by his executor or by the trustee of a trust. For purposes of this paragraph, an interest shall not be considered as an interest which will terminate or fail merely because it is the ownership of a bond, note, or similar contractual obligation, the discharge of which would not have the effect of an annuity for life or for a term. (2) Interest in unidentified assetsWhere the assets (included in the decedent’s gross estate) out of which, or the proceeds of which, an interest passing to the surviving spouse may be satisfied include a particular asset or assets with respect to which no deduction would be allowed if such asset or assets passed from the decedent to such spouse, then the value of such interest passing to such spouse shall, for purposes of subsection (a), be reduced by the aggregate value of such particular assets. (3) Interest of spouse conditional on survival for limited periodFor purposes of this subsection, an interest passing to the surviving spouse shall not be considered as an interest which will terminate or fail on the death of such spouse if—(A) such death will cause a termination or failure of such interest only if it occurs within a period not exceeding 6 months after the decedent’s death, or only if it occurs as a result of a common disaster resulting in the death of the decedent and the surviving spouse, or only if it occurs in the case of either such event; and