Fair use depends on several factors, including whether your use is transformative (you are copying the work in order to make a point -- for example, criticism or parody), the amount and substantiality of the portion borrowed, the nature of the work -- for example, fiction or nonfiction -- and the effect of the use on the market. Practically, you are better advised to read how the law is applied in cases such as the recent suit permitting the use of John Lennon's "Imagine" in a Ben Stein documentary. You can review case summaries at the Stanford Library Fair Use website.
There are also some wild card factors: Is the newspaper still in business? How likely is it that the owner will learn of your use? Will the owner care enough to pursue action? Will your copying affect your ability to obtain insurance? Finally, always keep in mind that fair use is an affirmative defense (not an affirmative right).
