In 1829, General Jackson appointed Mr. McLean to the bench of the Supreme Court of the United States, he having previously declined the War and Navy Departments, although the two men differed somewhat in their ideas of public policy. In January, 1830, he took his seat upon the bench, and since that time the only indications of Judge McLean's opinions on the political issues of modern times which the public could notice, have been afforded by his published decisions involving the question of slavery. Some years since, the private friends of Judge McLean were aware that he sympathized very deeply with the Anti-Slavery reformers of the West and North, and that he did not approve of the political principles of the Democratic party, as laid down in their regular platforms, on this subject. He may be safely set down as a conservative opponent of negro slavery, and its extension into the territories of the republic. In the last Presidential election he voted for John C. Fremont, which would seem to settle the question as to his political affinities. He is a Republican. From Judge McLean's opinion, delivered in the Dred Scott case, we gather his views upon some of the more prominent political issues of the day: "As to the locality of slavery. The civil law throughout the continent of Europe, it is believed, without an exception, is, that slavery can exist only within the territory where it is established; and that, if a slave escapes, or is carried beyond such territory, his master cannot reclaim him, unless by virtue of some express stipulation. "There is no nation in Europe which considers itself bound to return to his master a fugitive slave, under the civil law or the law of nations. On the contrary, the slave is held to be free where there is no treaty obligation, or compact in some other form, to return him to his master. The Roman law did not allow freedom to be sold. An ambassador or any other public functionary could not take a slave to France, Spain, or any other country in Europe, without emancipating him. A number of slaves escaped from a Florida plantation, and were received on board of ship by Admiral Cochrane; by the King's Bench, they were held to be free. In the great and leading case of Prigg _v._ the State of Pennsylvania, this court says that, by the general law of nations, no nation is bound to recognize the state of slavery, as found within its territorial dominions, where it is in opposition to its own policy and institutions, in favor of the subjects of other nations where slavery is organized. If it does it, it is as a matter of comity, and not as a matter of international right. The state of slavery is deemed to be a mere municipal regulation, founded upon and limited to the range of the territorial laws. This was fully recognized in Somerset's case, which was decided before the American Revolution.