You may be interested in several tabs on this Social Work Research Guide.  The Alumni Resources tab has a list of free policy databases.  Also within the Alumni Resources tab is a section for  free electronic books.  Several of the electronic books focus on government /policy information.  The Reference tab on this Research Guide has a subpage with free statistical resources.  Some of the free datasets may also be of interest.

Several Research Guides may be of interest:
     Social Policy-Brown School Library
          https://libguides.wustl.edu/socialpolicy-brownschool
     Washington University Elections Research Guide
          https://libguides.wustl.edu/elections
     Washington University Geographic Information Systems (GIS) Research Guide 
          https://libguides.wustl.edu/gis
     Washington University Government Research Guide
          https://libguides.wustl.edu/govtinfo
     Washington University Political Science Research Guide 
          https://libguides.wustl.edu/polisci