Stop Postal Closures Act This bill prohibits the U.S. Postal Service (USPS) from closing or consolidating postal facilities or carrying out any network rationalization activity until the Postal Regulatory Commission (PRC) has certified that the USPS has met specified national service standards. The bill also prohibits any future post office closures or consolidations, unless the PRC has approved the closure or consolidation using procedures specified in the bill. The PRC must also rate the performance of the USPS.