Are you looking for states which have laws against hate crimes or do you need a comparison on state election laws?   Hein Online has digitized a well known reference classic: Subject Compilations of State Laws by Cheryl Rae Nyberg and Carol Boast. This title has been published since 1979, however, the ability to search the entire 25 volume set on Hein and then link directly to full-text journal citations makes the online version a powerful resource.

Subject Compilations contains references to more than 17,000 sources of 50-state surveys published in law review articles, books, court briefs and opinions, federal and state government publications, and loose-leaf services.  It is expertly indexed with 319 subject headings and is a great place to begin multi-state research. 

There are numerous options for conducting multi-state research on the internet. Using state legislative home pages is an effective technique, particularly if you are only comparing a few states. Lexis and Westlaw are obvious research choices since each of these legal databases offer cross jurisdictional searching through cases, statutes, and regulations for all fifty states at once.

Additionally, both Lexis and Westlaw have specialized databases with state surveys. Legal researchers with access to both databases will notice format differences and date coverage differences but overall each vendor provides a strong collection for multi-state statutory research.   

Before starting the formidable task of surveying the law in fifty states, be sure to consult the Harvard Law School Multi-State Research Guide  which concisely outlines print and electronic resources helpful in these projects.