The policy you select should be the current law. The older the policy the more likely that policy will have amendments as well as research, legislative and public resources and commentary.
Each Congress proposes thousands of bills, but often only 200-300 usually make it into law. These individual laws are published as public laws by number, such as Public Law 105-89. (The 105 designates the 105th Congress; the 89 denotes that it is the 89th law passed by the 105th Congress).
A compilation of public laws is put together by subject to give us the current U.S. law. This compilation is called the U.S. Code. Since many of these laws are frequently amendments of an original law, you will want to use the U.S. Code to find the current law.
The site Congress.gov, provides the full text of laws from the 103rd Congress (1993-1994) to the current Congress and summaries from the 93rd congress to the current congress. For laws from the 103rd Congress (1993-1994) to the present Congress, there is a link to the Public Law via the United States Government Publishing Office.
When a federal law is passed, it authorizes a federal agency to write regulations to administer the law. For example the Adoption and Safe Families Act of 1997 authorized the State of Health and Human Services to write regulations that deal with the specifics in administering the law.