20. Definition through the History of the Case. In some cases the easiest way to put before your readers the precise details or limitations implied in a term is through a brief review of the history of the question. In the Lincoln-Douglas debates Lincoln was constantly showing that Douglas's use of the term "popular sovereignty" must be understood in the light of the whole history of the slavery question; that it meant one thing--what Douglas intended it to mean--if the history of the question before 1850 were left out of sight; but that it meant a wholly different thing if the steady encroachment of the slave power from the Missouri Compromise of 1820 on were taken into account. And Lincoln showed that in reality "popular sovereignty" had come to mean a power oh the part of the people of a territory to introduce slavery, but not to exclude it.[12] In our own day "progressive" has a different meaning when applied to a Republican from Kansas and to one from Massachusetts or New York.
To know just what is involved by applying the term to any given public man, one must go back to the recent history of his party in his own state, and to the speeches he has made. In political discussions popular phrases are constantly thus blurred in meaning through being used as party catchwords; and to use them with any certainty in an argument one must thus go back to their origin, and then dissect out, as it were, the ambiguous implications which have grown into them.
If you were arguing any question concerning the elective system or the entrance requirements for your own college, you would often do well to sketch the history of the present system as a means of defining it, before you go on to urge that it be changed or kept as it is. So if you were arguing for a further change in the football rules, your best definition of the present game for your purpose would be a sketch of the way in which the game has been changed in the past few years, at the urgent demand of public opinion. Such a sketch you could easily get by running through the back numbers of such a magazine as _Outing_, or the sporting columns of some of the larger weeklies. Or again, if you were arguing that the street railway systems of your city should be allowed to combine, your best description or definition of the present situation might well be a sketch of the successive steps by which it came to be what it is. Here you would go for your material to the files of local newspapers, or, if you could get at them, to sets of the reports of the railway companies.