As soon as a topic engages your interest, you should conduct a preemption check. The purpose of a preemption check is to determine if an author has covered your topic in a substantial article, or book, and if a court case or piece of legislation will resolve your topic. You do not want to devote time to a topic that has already been examined exhaustively or that will be rendered meaningless by a forthcoming court decision or enacted law. However, a topic that has been addressed by other authors still may be a valid choice if you can make a unique argument or change jurisdictions.
Preemption checks begin when you start your topic research and must be repeated regularly until publication. Follow these preemption check steps before you settle on your topic and thesis, while you are still researching a wider variety of sources for ideas. Repeat the process below, frequently, until you submit your final draft.
Step 1: Search full-text law review databases.
Your search should include full text articles in Law Reviews and Journals in Lexis, Law Reviews and Journals in Westlaw, and the Law Journal Library and smaller periodicals (e.g., Bar Journals) in HeinOnline. Use Scholar Check in Hein to help locate citing materials for particular articles or authors. While these databases overlap to some extent, you should still check each one because the contents and dates of coverage vary.
Step 2: Search legal periodicals indexes.
Your search should include the Legal Resource Index on Westlaw, LegalTrac, which is available on the Eckstein Library homepage. These indexes include many more articles than the full-text journal databases. When you search an index, you are not searching the full text of an article, so you will search by subject. If you locate an abstract on LegalTrac or in Legal Resource Index that appears relevant, you can look for the full text article on HeinOnline, Lexis or Westlaw, or in print.
If you are working on a foreign, comparative or international law topic, consult the Index to Foreign Legal Periodicals. It is available in HeinOnline and in print at the Eckstein Law Library, Call Number K33. I53. Note: the print version is not updated.
Important! If you are researching an issue with interdisciplinary (non-legal) dimensions, search full text databases from the appropriate disciplines. Start with MarqcatPlus, which aggregates several Raynor Library databases. Also conduct research in appropriate subject databases on the Raynor databases page.
Use indexes appropriate to the discipline, too. Indexes will be listed along with full text databases on Raynor’s list of databases by subject. Ask for help if you are having difficulty or think you might be missing some relevant databases.
Step 3: Search for books (and book chapters) covering your topic.
Use the catalog called WorldCat. It will allow you to search thousands of library catalogs simultaneously. WorldCat results include books, serials, mixed media, and can be sorted.
Step 4: Search working papers.
You should search both SSRN and bepress. Both repositories will allow you to see what authors are working on before the articles are formally published. SSRN has more disciplines that law, and there are millions of articles. Rather than limit the database to just law, you could search with very tailored search terms to elicit non-legal articles that might be similar to your topic. Try searching broadly and narrowly on SSRN. In the bepress legal repository, be sure to chose the "across all repositories" option so you are not just searching Marquette's repository.
Step 5: KeyCite and Shepardize any cases and statutes that are at the heart of your topic.
For cases, check Shepard's and KeyCite to see if there is any subsequent history, including whether a petition for review has been filed. For statutes, check to see if there is proposed legislation that could substantially change the law.
Using two citators is a very good idea for preemption checks, as they operate slightly differently and something may turn up more obviously in one. Bloomberg Law’s BCite is also a good citator option for primary law.