The exact time when this movement was begun cannot now be ascertained.  The motives which prompted it can be inferred by recalling contemporaneous political events.  A great controversy divided public opinion, whether slavery might be extended or should be restricted.  The Missouri Compromise had been repealed to make such an extension possible.  The terms of that repeal were purposely couched in ambiguous language.  Kansas and Nebraska were left “perfectly free to form and regulate their domestic institutions in their own way, subject only to the Constitution of the United States.”  Whether under the Constitution slavery could be excluded from the Federal Territories was affirmed by Northern and denied by Southern Democrats.  Northern and Southern Democrats, acting together in the Cincinnati National Convention, had ingeniously avoided any solution of this difference.

A twofold interpretation had enabled that party to elect Mr. Buchanan, not by its own popular strength, but by the division of its opponents.  Notwithstanding its momentary success, unless it could develop new sources of strength the party had only a precarious hold upon power.  Its majority in the Senate was waning.  In Kansas free-State emigration was outstripping the South in numbers and checkmating her in border strife.  According to the existing relative growth in sectional representation and sectional sentiment, the balance of power was slowly but steadily passing to the North.

Out of this doubt and difficulty there was one pathway that seemed easy and certain.  All the individual utterances from the Democratic party agreed that the meaning of the words “subject to the Constitution” was a question for the courts.  This was the original compact between Northern and Southern Democrats in caucus when Douglas consented to repeal.  Douglas, shorn of his prestige by his defeat for the Presidential nomination, must accept conditions from his successful rival.  The Dred Scott case afforded the occasion for a decision.  Of the nine judges on the Supreme Bench seven were Democrats, and of these five were appointed from slave-States.  A better opportunity for the South to obtain a favorable dictum could never be expected to arise.  A declaration by the Supreme Court of the United States that under the Constitution Congress possessed no power to prohibit slavery in the Federal Territories would by a single breath end the old and begin a new political era.  Congress was in session and the political leaders were assembled at Washington.  Political topics excluded all other conversation or thought.  Politics reddened the plains of Kansas; politics had recently desecrated the Senate chamber with a murderous personal assault; politics contended greedily for the spoils of a new administration:  politics nursed a tacit conspiracy to nationalize slavery.  The slavery sentiment ruled society, ruled the Senate, ruled the Executive Mansion.  It is not surprising that this universal influence flowed in at the open door of the national hall of justice—­that it filtered through the very walls which surrounded the consulting-room of the Supreme Court.