In organizing governments over these territories no duty imposed on Congress by the Constitution requires that they should legislate on the subject of slavery, while their power to do so is not only seriously questioned, but denied by many of the soundest expounders of that instrument.  Whether Congress shall legislate or not, the people of the acquired territories, when assembled in convention to form State constitutions, will possess the sole and exclusive power to determine for themselves whether slavery shall or shall not exist within their limits.  If Congress shall abstain from interfering with the question, the people of these territories will be left free to adjust it as they may think proper when they apply for admission as States into the Union.  No enactment of Congress could restrain the people of any of the sovereign States of the Union, old or new, North or South, slaveholding or nonslaveholding, from determining the character of their own domestic institutions as they may deem wise and proper.  Any and all the States possess this right, and Congress can not deprive them of it.  The people of Georgia might if they chose so alter their constitution as to abolish slavery within its limits, and the people of Vermont might so alter their constitution as to admit slavery within its limits.  Both States would possess the right, though, as all know, it is not probable that either would exert it.

It is fortunate for the peace and harmony of the Union that this question is in its nature temporary and can only continue for the brief period which will intervene before California and New Mexico may be admitted as States into the Union.  From the tide of population now flowing into them it is highly probable that this will soon occur.

Considering the several States and the citizens of the several States as equals and entitled to equal rights under the Constitution, if this were an original question it might well be insisted on that the principle of noninterference is the true doctrine and that Congress could not, in the absence of any express grant of power, interfere with their relative rights.  Upon a great emergency, however, and under menacing dangers to the Union, the Missouri compromise line in respect to slavery was adopted.  The same line was extended farther west in the acquisition of Texas.  After an acquiescence of nearly thirty years in the principle of compromise recognized and established by these acts, and to avoid the danger to the Union which might follow if it were now disregarded, I have heretofore expressed the opinion that that line of compromise should be extended on the parallel of 36° 30’ from the western boundary of Texas, where it now terminates, to the Pacific Ocean.  This is the middle ground of compromise, upon which the different sections of the Union may meet, as they have heretofore met.  If this be done, it is confidently believed a large majority of the people of every section of the country, however widely their abstract opinions on the subject of slavery may differ, would cheerfully and patriotically acquiesce in it, and peace and harmony would again fill our borders.