LIMITATION ON ALTERATION OF THE NAVY FLEET MIX.

SEC. 121. LIMITATION ON ALTERATION OF THE NAVY FLEET MIX. (a) Limitation.— (1) In general.—The Secretary of the Navy may not deviate from the large surface combatant requirements included in the 2016 Navy Force Structure Assessment until the date on which the Secretary submits to the congressional defense committees the certification under paragraph (2) and the report under subsection (b). (2) Certification.—The certification referred to in paragraph (1) is a certification, in writing, that the Navy can mitigate the reduction in multi-mission large surface combatant requirements, including anti-air and ballistic missile defense capabilities, due to having a reduced number of DDG-51 Destroyers with the advanced AN/SPY-6 radar in the next three decades. (b) Report.—Not later than 90 days after the date of the enactment of this Act, the Secretary of the Navy shall submit to the congressional defense committees a report that includes— (1) a description of likely detrimental impacts to the large surface combatant industrial base, and a plan to mitigate such impacts, if the fiscal year 2021 future-years defense program is implemented as proposed; (2) a review of the benefits to the Navy fleet of the new AN/SPY-6 radar to be deployed aboard Flight III variant DDG-51 Destroyers, which are currently under construction, as well as an analysis of impacts to the warfighting capabilities of the fleet should the number of such destroyers be reduced; and (3) a plan to fully implement section 131 of the National Defense Authorization for Fiscal Year 2020 (Public Law 116-92; 133 Stat. 1237), including subsystem prototyping efforts and funding by fiscal year.