If a passage is quoted verbatim, it must be set off with quotation marks (or, if it is a longer passage, presented as indented text), and followed by a properly formulated citation ... even if only a few words are involved.

Plagiarism guidelines posted on the website of the Naval Postgraduate School, where David Clarke -- the Milwaukee County Sheriff who will be leaving for a gig at the U.S. Department of Homeland Security -- got his master's degree. According to CNN, Clarke plagiarized in at least 47 parts of his thesis.