Spectrum Management And Reallocation for Taxpayers Act or the SMART Act This bill authorizes the Federal Communications Commission (FCC) to conduct a public auction of mid-band spectrum and places requirements on how the FCC must use the proceeds from such an auction. Specifically, the bill authorizes the FCC to identify, clear, and auction mid-band spectrum. The bill also establishes a (1) C-Band Reimbursement and Implementation Fund to reimburse costs and incentivize license holders to reduce their usage of spectrum so that it may be auctioned, (2) Digital Divide Trust Fund for deployment of broadband infrastructure in unserved and underserved areas, and (3) Next Generation 9–1–1 Trust Fund for deployment of upgraded 9–1–1 services that use a digital or internet protocol-based system. The FCC must use the proceeds from a spectrum auction authorized under this bill to (1) reimburse amounts borrowed from the general fund of the Treasury that were deposited into the C-Band Reimbursement and Implementation Fund, (2) deposit a specified amount into the general fund of the Treasury for the purpose of deficit reduction, and (3) deposit all remaining amounts in the Digital Divide Trust Fund and the Next Generation 9–1–1 Trust Fund. Additionally, the bill prohibits an entity that poses a national security risk from participating in a spectrum auction.