The idea of a preemption check is simply to check to see if your topic has been done before. Often paper authors get very far in their research before discovering that their topic, thesis, and focus was sufficiently covered in others' works.
Find papers on your subject? Good! Now you can refocus your paper and you now have an excellent source. Consider:
Run a preemption check early and you will not only save yourself time and disappointment, but will certainly end up with a better focus and scholarship.
Be sure to set alerts, or at least keep updating with the citator of your choice, any cases, statutes, or regulations which are at the heart of your paper topic.
See the Keeping Current tab in this guide for more.