Source: James K. Polk, Fourth Annual Message, online, by Gerhard Peters and John T. Woolley, The American Presidency Project https://www.presidency.ucsb.edu/node/200618.

. . . The great results which have been developed and brought to light by this war will be of immeasurable importance in the future progress of our country. They will tend powerfully to preserve us from foreign collisions, and to enable us to pursue uninterruptedly our cherished policy of “peace with all nations, entangling alliances with none.”^[1]

Occupying, as we do, a more commanding position among nations than at any former period, our duties and our responsibilities to ourselves and to posterity are correspondingly increased. This will be the more obvious when we consider the vast additions which have been recently made to our territorial possessions and their great importance and value.

Within less than four years the annexation of Texas to the Union has been consummated; all conflicting title to the Oregon Territory south of the forty-ninth degree of north latitude, being all that was insisted on by any of my predecessors, has been adjusted, and New Mexico and Upper California have been acquired by treaty.^[2] The area of these several territories, according to a report carefully prepared by the commissioner of the General Land Office from the most authentic information in his possession, and which is herewith transmitted, contains 1,193,061 square miles, or 763,559,040 acres; while the area of the remaining twenty-nine states and the territory not yet organized into states east of the Rocky Mountains contains 2,059,513 square miles, or 1,318,126,058 acres. These estimates show that the territories recently acquired, and over which our exclusive jurisdiction and dominion have been extended, constitute a country more than half as large as all that which was held by the United States before their acquisition. . . .

It would be difficult to calculate the value of these immense additions to our territorial possessions. Texas, lying contiguous to the western boundary of Louisiana, embracing within its limits a part of the navigable tributary waters of the Mississippi and an extensive seacoast, could not long have remained in the hands of a foreign power without endangering the peace of our southwestern frontier. Her products in the vicinity of the tributaries of the Mississippi must have sought a market through these streams, running into and through our territory, and the danger of irritation and collision of interests between Texas as a foreign state and ourselves would have been imminent, while the embarrassments in the commercial intercourse between them must have been constant and unavoidable. Had Texas fallen into the hands or under the influence and control of a strong maritime or military foreign power, as she might have done, these dangers would have been still greater. They have been avoided by her voluntary and peaceful annexation to the United States. Texas, from her position, was a natural and almost indispensable part of our territories. Fortunately, she has been restored to our country, and now constitutes one of the states of our confederacy,^[3] “upon an equal footing with the original states.”^[4] The salubrity of climate, the fertility of soil, peculiarly adapted to the production of some of our most valuable staple commodities, and her commercial advantages must soon make her one of our most populous states.

New Mexico, though situated in the interior and without a seacoast, is known to contain much fertile land, to abound in rich mines of the precious metals, and to be capable of sustaining a large population. From its position it is the intermediate and connecting territory between our settlements and our possessions in Texas and those on the Pacific Coast.

Upper California, irrespective of the vast mineral wealth recently developed there, holds at this day, in point of value and importance, to the rest of the Union the same relation that Louisiana did when that fine territory was acquired from France forty-five years ago. Extending nearly ten degrees of latitude along the Pacific, and embracing the only safe and commodious harbors on that coast for many hundred miles, with a temperate climate and an extensive interior of fertile lands, it is scarcely possible to estimate its wealth until it shall be brought under the government of our laws and its resources fully developed. From its position it must command the rich commerce of China, of Asia, of the islands of the Pacific, of western Mexico, of Central America, the South American states, and of the Russian possessions bordering on that ocean. A great emporium will doubtless speedily arise on the Californian coast which may be destined to rival in importance New Orleans itself. The depot of the vast commerce which must exist on the Pacific will probably be at some point on the Bay of San Francisco, and will occupy the same relation to the whole western coast of that ocean as New Orleans does to the valley of the Mississippi and the Gulf of Mexico. To this depot our numerous whale ships will resort with their cargoes to trade, refit, and obtain supplies. This of itself will largely contribute to build up a city, which would soon become the center of a great and rapidly increasing commerce. Situated on a safe harbor, sufficiently capacious for all the navies as well as the marine of the world, and convenient to excellent timber for shipbuilding, owned by the United States, it must become our great western naval depot.

It was known that mines of the precious metals existed to a considerable extent in California at the time of its acquisition. Recent discoveries render it probable that these mines are more extensive and valuable than was anticipated. The accounts of the abundance of gold in that territory are of such an extraordinary character as would scarcely command belief were they not corroborated by the authentic reports of officers in the public service who have visited the mineral district and derived the facts which they detail from personal observation. Reluctant to credit the reports in general circulation as to the quantity of gold, the officer commanding our forces in California visited the mineral district in July last for the purpose of obtaining accurate information on the subject. His report to the War Department of the result of his examination and the facts obtained on the spot is herewith laid before Congress. When he visited the country there were about four thousand persons engaged in collecting gold. There is every reason to believe that the number of persons so employed has since been augmented. The explorations already made warrant the belief that the supply is very large and that gold is found at various places in an extensive district of country.

Information received from officers of the Navy and other sources, though not so full and minute, confirms the accounts of the commander of our military force in California. It appears also from these reports that mines of quicksilver are found in the vicinity of the gold region. One of them is now being worked, and is believed to be among the most productive in the world.

The effects produced by the discovery of these rich mineral deposits and the success which has attended the labors of those who have resorted to them have produced a surprising change in the state of affairs in California. Labor commands a most exorbitant price, and all other pursuits but that of searching for the precious metals are abandoned. Nearly the whole of the male population of the country have gone to the gold districts. Ships arriving on the coast are deserted by their crews and their voyages suspended for want of sailors. Our commanding officer there entertains apprehensions that soldiers cannot be kept in the public service without a large increase of pay. Desertions in his command have become frequent, and he recommends that those who shall withstand the strong temptation and remain faithful should be rewarded. . . .

The powers of Europe, far removed from the west coast of America by the Atlantic Ocean, which intervenes, and by a tedious and dangerous navigation around the southern cape of the continent of America, can never successfully compete with the United States in the rich and extensive commerce which is opened to us at so much less cost by the acquisition of California.

The vast importance and commercial advantages of California have heretofore remained undeveloped by the government of the country of which it constituted a part. Now that this fine province is a part of our country, all the states of the Union, some more immediately and directly than others, are deeply interested in the speedy development of its wealth and resources. No section of our country is more interested or will be more benefited than the commercial, navigating, and manufacturing interests of the eastern states. Our planting and farming interests in every part of the Union will be greatly benefited by it. As our commerce and navigation are enlarged and extended, our exports of agricultural products and of manufactures will be increased, and in the new markets thus opened they cannot fail to command remunerating and profitable prices.

The acquisition of California and New Mexico, the settlement of the Oregon boundary, and the annexation of Texas, extending to the Rio Grande, are results which, combined, are of greater consequence and will add more to the strength and wealth of the nation than any which have preceded them since the adoption of the Constitution. . . .

It is our solemn duty to provide with the least practicable delay for New Mexico and California regularly organized territorial governments. The causes of the failure to do this at the last session of Congress are well known and deeply to be regretted. With the opening prospects of increased prosperity and national greatness which the acquisition of these rich and extensive territorial possessions affords, how irrational it would be to forgo or to reject these advantages by the agitation of a domestic question which is coeval with the existence of our government itself,^[5] and to endanger by internal strifes, geographical divisions, and heated contests for political power, or for any other cause, the harmony of the glorious Union of our confederated states—that Union which binds us together as one people, and which for sixty years has been our shield and protection against every danger. In the eyes of the world and of posterity how trivial and insignificant will be all our internal divisions and struggles compared with the preservation of this Union of the states in all its vigor and with all its countless blessings! No patriot would foment and excite geographical and sectional divisions. No lover of his country would deliberately calculate the value of the Union. Future generations would look in amazement upon the folly of such a course. Other nations at the present day would look upon it with astonishment, and such of them as desire to maintain and perpetuate thrones and monarchical or aristocratical principles will view it with exultation and delight, because in it they will see the elements of faction, which they hope must ultimately overturn our system. Ours is the great example of a prosperous and free self-governed republic, commanding the admiration and the imitation of all the lovers of freedom throughout the world. How solemn, therefore, is the duty, how impressive the call upon us and upon all parts of our country, to cultivate a patriotic spirit of harmony, of good-fellowship, of compromise and mutual concession, in the administration of the incomparable system of government formed by our fathers in the midst of almost insuperable difficulties, and transmitted to us with the injunction that we should enjoy its blessings and hand it down unimpaired to those who may come after us.

In view of the high and responsible duties which we owe to ourselves and to mankind, I trust you may be able at your present session to approach the adjustment of the only domestic question which seriously threatens, or probably ever can threaten, to disturb the harmony and successful operations of our system.

The immensely valuable possessions of New Mexico and California are already inhabited by a considerable population. Attracted by their great fertility, their mineral wealth, their commercial advantages, and the salubrity of the climate, emigrants from the older states in great numbers are already preparing to seek new homes in these inviting regions. Shall the dissimilarity of the domestic institutions in the different states prevent us from providing for them suitable governments? These institutions existed at the adoption of the Constitution, but the obstacles which they interposed were overcome by that spirit of compromise which is now invoked. In a conflict of opinions or of interests, real or imaginary, between different sections of our country, neither can justly demand all which it might desire to obtain. Each, in the true spirit of our institutions, should concede something to the other. . . .

The whole people of the United States, and of every state, contributed to defray the expenses of that war, and it would not be just for any one section to exclude another from all participation in the acquired territory. This would not be in consonance with the just system of government which the framers of the Constitution adopted.

The question is believed to be rather abstract than practical whether slavery ever can or would exist in any portion of the acquired territory even if it were left to the option of the slaveholding states themselves. From the nature of the climate and productions in much the larger portion of it, it is certain it could never exist, and in the remainder the probabilities are it would not. But however this may be, the question, involving, as it does, a principle of equality of rights of the separate and several states as equal copartners in the confederacy, should not be disregarded.

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 cannot 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.

The restriction north of the line was only yielded to in the case of Missouri and Texas upon a principle of compromise, made necessary for the sake of preserving the harmony and possibly the existence of the Union.

It was upon these considerations that at the close of your last session I gave my sanction to the principle of the Missouri compromise line by approving and signing the bill to establish “the Territorial government of Oregon.” From a sincere desire to preserve the harmony of the Union, and in deference for the acts of my predecessors, I felt constrained to yield my acquiescence to the extent to which they had gone in compromising this delicate and dangerous question. But if Congress shall now reverse the decision by which the Missouri compromise was effected, and shall propose to extend the restriction over the whole territory, south as well as north of the parallel of 36°30′, it will cease to be a compromise, and must be regarded as an original question.

If Congress, instead of observing the course of noninterference, leaving the adoption of their own domestic institutions to the people who may inhabit these territories, or if, instead of extending the Missouri compromise line to the Pacific, shall prefer to submit the legal and constitutional questions which may arise to the decision of the judicial tribunals, as was proposed in a bill which passed the Senate at your last session, an adjustment may be effected in this mode. If the whole subject be referred to the judiciary, all parts of the Union should cheerfully acquiesce in the final decision of the tribunal created by the Constitution for the settlement of all questions which may arise under the Constitution, treaties, and laws of the United States.^[6]

Congress is earnestly invoked, for the sake of the Union, its harmony, and our continued prosperity as a nation, to adjust at its present session this, the only dangerous question which lies in our path, if not in some one of the modes suggested, in some other which may be satisfactory. . . .