The U.S. Federal Government is the world's largest research organization.   Here are some tools which can be used to find Federal Government research on Presidential polciies, actions, etc.

Federal Government Oversight Agencies

Congressional Research Service, Congressional Budget Office, and General Accountancy Office are excellent sources of expert and non-partisan studies of government.

ProQuest Congressional

Access to nearly every document created by Congress, including committee hearings.

Catalog of U.S. Government Publications

General-purpose finding tool for publications from a wide range of agencies.

You have access to various collections of official U.S. Presidential documents.