(18) Maintenance of state financial support.--
(A) In general.--The State does not reduce the amount of State financial support for special education and related services for children with disabilities, or otherwise made available because of the excess costs of educating those children, below the amount of that support for the preceding fiscal year.
(B) Reduction of funds for failure to maintain support.--The Secretary shall reduce the allocation of funds under section 611 for any fiscal year following the fiscal year in which the State fails to comply with the requirement of subparagraph (A) by the same amount by which the State fails to meet the requirement.
(C) Waivers for exceptional or uncontrollable circumstances.--The Secretary may waive the requirement of subparagraph (A) for a State, for 1 fiscal year at a time, if the Secretary determines that--
(i) granting a waiver would be equitable due to exceptional or uncontrollable circumstances such as a natural disaster or a precipitous and unforeseen decline in the financial resources of the State; or
(ii) the State meets the standard in paragraph (17)(C) for a waiver of the requirement to supplement, and not to supplant, funds received under this part.
(D) Subsequent years.--If, for any year, a State fails to meet the requirement of subparagraph (A), including any year for which the State is granted a waiver under subparagraph (C), the financial support required of the State in future years under subparagraph (A) shall be the amount that would have been required in the absence of that failure and not the reduced level of the State's support.