Creates a new national-security duty for management of the Thrift Savings Fund (TSP), directs rulemaking on how that duty applies to investments and shareholder voting, bans mutual funds available through the TSP mutual fund window from buying securities of China-based entities, and provides a short, limited immunity for fiduciaries who do not meet the new national-security duty until January 1, 2027. It also requires the Secretary of Labor to lead interagency rulemaking with Defense, Justice, Homeland Security, and Treasury and to deliver recurring reports to Congress on compliance reviews and enforcement outcomes.