The case of Prigg v. Pennsylvania30 illustrates the value of a resort to the "history of the times" and to the general object sought to be obtained, in interpreting an ambiguous constitutional provision. In this case, which involved the question as to the ex-clusiveness of the power granted to the Federal Government under the fugitive slave clause of the Constitution,34 Justice Story said: "Historically it is well known that the object of this clause was to secure to the citizens of the slaveholding States the complete right and title of ownership in their slaves, as property, in every State in the Union into which they might escape from the State where they were held in servitude. . . . How then are we to interpret the language of the clause? The true answer is, in such a manner, as, consistently with the words, shall fully and completely effectuate the whole object of it. If by one mode of interpretation the right must become shadowy and unsubstantial, and without any remedial powers adequate to the end, and by another mode it will attain its just end and secure its manifest purpose, it would seem upon principles of reasoning absolutely irresistible that the latter ought to obtain. No court of justice can be authorized so to construe any clause of the Constitution as to defeat its obvious ends, when another construction equally accordant with the words and sense thereof will enforce and protect them."

28 In Cohens v. Virginia (6 Wh. 264; 5 L. ed. 527) Marshall says: "The opinion of The Federalist has always been considered as of great authority. It is a earoplete commentary on our Constitution; and is appealed to by all parties in the questions to which that instrument has given birth. Its intrinsic merit entitles it to this high rank; and the part two of its authors performed in framing the Constitution, puts it very much in their power to explain the views with which it was framed. These essays having been published while the Constitution was before the nation for adoption or rejection, and having been written in answer to objections founded entirely on the extent of its powers, and on its diminution of state sovereignty, are entitled to the more consideration where they frankly avow that the power objected to is given, and defend it."

29 2 Dall. 419; 1 L. ed. 440.

30 16 Tet. 530; 10 L. ed. 1060. 31 Art. IV, Sec. II, Cl. 3.

Here it is to be observed that Story properly introduces the qualifying condition that the construction supported by the history of the times in which, and the purpose for which, it was formed, must, as compared with another possible construction, be "equally accordant with the words and sense thereof." It is thus to be emphasized that extrinsic evidence may never be used to support an interpretation which the written word does not upon its face reasonably permit. In other words, extrinsic evidence may properly be used to decide between two possible constructions of the written word, but not to add to or subtract from its express provisions.32