墨西哥军事、国力比美国差非常多，为什么美国不去侵略占领吞并它？

我翻了全部378個回答，除了一兩個可能擦邊的之外，沒有一個提到了美墨戰爭期間聲勢浩大的"吞並全墨西哥運動（All of Mexico Movement^[1]）“，結果這問題幾乎完全成了一個腦洞問題？先生們真是讓人佩服得緊。

本文準備先簡單說下什麼是”吞併全墨西哥運動“，然後我們再翻翻美文老檔，看看當時的極富影響力的美國政治三巨頭（Great Triumvirate^[2]）之一卡爾霍恩（John C. Calhoun^[3]）是如何在參議院以一篇冗長的演講激烈反對這個全盤吞併墨西哥的運動的。

1、”全墨西哥運動“（這部分我直接貼wiki了）

全墨西哥運動是一場政治運動，旨在擴大美國以吞並整個墨西哥。這是昭昭天命（Manifest Destiny^[4]）思潮的表征之一，但從未實現。1846-1848 年的美墨戰爭（使美國）征服了加利福尼亞和墨西哥北部其他人煙稀少的領土，同時美國軍隊也入侵了人口稠密的墨西哥腹地。
在美國軍隊占領墨西哥城後，（部分）美國人重新燃起了整合整個墨西哥的熱情。這個想法在美國國會遭到強烈反對，尤其是來自南卡羅來納州的美國參議員約翰·C·卡爾霍恩 ( John C. Calhoun )，他強烈反對將非白人人口密集的領土並入其中^[5] 。
......
到1847年夏天，美國在戰場上取得的成功鼓勵了吞並整個墨西哥的呼聲，尤其是東部民主黨人的呼聲，他們認為將墨西哥納入聯邦是確保該地區和平的最佳方式。
......
吞並整個墨西哥的提議引起了爭議。天定命運的理想主義擁護者，如約翰·L·奧沙利文 ( John L. O'Sullivan ^[6] )——他是天定命運思潮最主要的推動者之一，一直認為美國的法律不應違背人的意願強加於人。吞並整個墨西哥將違反這一原則，且通過美國公民身份授予數百萬墨西哥人，將引發爭議。
這場辯論將昭昭天命的矛盾之一推到了最前沿。天定命運中固有的」同一性思想 「表明，作為非白人的墨西哥人會對白人種族完整性構成威脅，因此沒有資格成為美國公民，但天定命運的「使命」部分表明墨西哥人將得到改善，並將他們帶入美國的民主。同一性主義^[7]促進了天定命運，但正如卡爾霍恩和對運動的抵抗一樣，同一性主義也被用來反對天定命運。
完全吞並「全墨西哥」的支持者將其視為一項反奴隸製措施。
許多美國人對墨西哥的天主教、軟弱的共和主義和民族主義高漲的威脅感到困擾。

該運動在《瓜達盧佩-伊達爾戈條約》簽署後，迅速歸於沉寂。

2、時任參議員的約翰·C·卡爾霍恩為反對全盤吞併墨西哥在參議院發表的演說節錄

SPEECH On his Resolutions in reference to the War with Mexico, delivered in the Senate, January 4th, 1848.

But much as I regard military glory— much as I rejoice to witness the display of that indomitable energy and courage which surmounts all difficulties—I would be sorry indeed that our Government should lose any portion of that high character for justice, moderation, and discretion, which distinguished it in the early stages of our history.

大意是雖然軍事榮譽很重要，但是這場戰爭並不符合建國以來更多遵循的道德原則。這段話全是道德考慮，從利益角度來說乏善可陳，但是他將道德因素作為第一條反對理由，必然意味著代表了部分選民的心聲。

比如說美國哲學家亨利·戴維·梭羅就是因為反對這場戰爭和奴隸制而拒絕向馬薩諸塞州政府繳納人頭稅，因而被關進了監獄。迅速出獄後，他寫下了著名的《公民抗命論》（Civil disobedience^[8]）。

The next reason assigned is, that either holding Mexico as a province, or incorporating her into the Union, would be unprecedented by any example in our history.We have conquered many of the neighboring tribes of Indians, but we have never thought of holding them in subjection, or of incorporating them into our Union.They have been left as an independent people in the midst of us, or been driven back into the forests.Nor have we ever incorporated into the Union any but the Caucasian race.

下一個理由是，無論是在墨西哥設省，還是將她並入聯邦，這在我們的歷史上都是前所未有的。 我們已經征服了許多鄰近的印第安人部落，但我們從未想要融合，或將他們並入我們的聯邦。他們作為一個獨立的民族留在我們中間，或者被趕入叢林。我們從未將高加索人種之外的人民納入聯邦。

顯然第二個原因是種族主義黑屁（提示：後面還有很多這樣的黑屁），當代人可以直接蔑視之，但是毫無疑問的是在當時這一思想足以作為論據使用。

The great misfortune of what was formerly Spanish America, is to be traced to the fatal error of placing the colored race on an equality with the white. This error destroyed the social arrangement which formed the basis of their society. This error we have wholly escaped;

前西班牙美洲的巨大不幸可追溯到將有色人種與白人平等對待的致命錯誤。 這個錯誤破壞了構成他們社會基礎的社會安排。而我們（指美國）完全避免了這個錯誤；

It is a remarkable fact in this connection, that in the whole history of man, as far as my information extends, there is no instance whatever of any civilized colored race, of any shade, being found equal to the establishment and maintenance of free government, although by far the largest proportion of the human family is composed of them; and even in the savage state, we rarely find them anywhere with such governments, except it be our noble savages;

還是種族主義黑屁，大意是目前沒有任何有色人種建立民主政府的先例，因此他認為將墨西哥人併入一個民主國家是會水土不服的。

Are we to associate with ourselves, as equals, companions, and fellow-citizens, the Indians and mixed races of Mexico? I would consider such association as degrading to ourselves, and fatal to our institutions.

我們是否要以平等、夥伴和同胞的身份與墨西哥的印第安人和混血兒相處？ 我會認為這樣的安排會讓我們墮落，這我們的製度來說是致命的。

精神分裂的種族主義+1，前面剛說了認為墨西哥人是混血種無法適應美國的自由制度，下一句就談起我們的種族和制度碰上墨西哥人會墮落——到底誰適應不了誰？

There is not an example on record of any free state holding a province of the same extent and population, without disastrous consequences. The nations conquered and held as a province, have, in time, retaliated by destroying the liberty of their conquerors, through the corrupting effect of extended patronage and irresponsible power.

這段話應該是卡爾霍恩讀歷史得出的教訓，大意是像墨西哥（南部）這樣的領土規模和人口密度無法採用美式民主制度，而是必須要通過擴大行政權力進行”統制“，這種不受約束的擴權過程會腐蝕征服者的自由和力量。

The conquest of Mexico would add so vastly to the patronage of this Government, that it would absorb the whole powers of the States; the Union would become an imperial power, and the States reduced to mere subordinate corporations.

征服墨西哥會極大地加強聯邦政府的力量，進而它會攫取各州的全部權力； 聯邦將成為一個帝國力量，而各州將淪為純粹的附屬品。

這是一個非常現實的擔憂，因為當時墨西哥人口足足有900萬，而美聯邦也不過2000萬人，在加上他前述的墨西哥地區可能長時間內只能由聯邦政府使用行政權力統治，這就會極大的增強聯邦政府的力量。墨西哥提供的財力和軍力，甚至能使聯邦政府不再依靠美國本土各州就能自行其是，這是任何一個州權主義者都不願意看到的。

The end would be anarchy or despotism, as certain as I am now addressing the Senate.

隨後他繼續預言說，由於征服墨西哥帶來的前述影響，權力將前所未有的向總統集中，爭奪總統位置的鬥爭將愈加激烈，直到以一種獨裁政府和無政府狀態收場。

Let it not be said that Great Britain is an example to the contrary; that she holds provinces of vast extent and population, without materially impairing the liberty of the subject, or exposing the Government to violence, anarchy, confusion, or corruption. It is so. But it must be attributed to the peculiar character of her government. Of all governments that ever existed, of a free character, the British far transcends all in one particular, and that is, its capacity to bear patronage without the evils usually incident to it.

接著他說肯定有人要拿不列顛的情況來反駁我，該國確實在廣大領土和稠密人口的情況下維持了自由制度，且沒有陷入混亂、獨裁或無政府狀態。但是，英國很特殊，英國政府有能力在抑制負面影響的情況下，擴張行政權力。

in a few words, that it results from the fact that her Executive and the House of Lords (the conservative branches of her Government) are both hereditary, while the other House of Parliament has a popular character.

至於為什麼，這位先生認識是該國的兩院制度十分特殊，上議院世襲，而下議院親民。總之就是我們美國國情跟英國不同，所以他們那套我們不能學.jpg

when the Roman power passed beyond the limits of Italy, crossed the Adriatic, the Mediterranean, and the Alps, liberty fell prostrate;
......
Now, on the contrary, we see England, with subject-provinces of vastly greater territorial extent, and probably of not inferior population (I have not compared them); we see her, I repeat, going on without the personal liberty of the subject being materially impaired, or the Government subject to violence or anarchy!
......
Yet England has not wholly escaped the curse which must ever befall a free government which holds extensive provinces in subjection; for, although she has not lost her liberty, or fallen into anarchy, yet we behold the population of England crushed to the earth by the superincumbent weight of debt and taxation, which may one day terminate in revolution. The wealth derived from her conquests and provincial possessions may have contributed to swell the overgrown fortunes of the upper classes, but has done nothing to alleviate the pressure on the laboring masses below. On the contrary, the expenses incident to their conquest, and of governing and holding them in subjection, have been drawn mainly from their labor, and have increased instead of decreasing the weight of the pressure. It has placed a burden upon them which, with all their skill and industry, with all the vast accumulation of capital and power of machinery with which they are aided, — they are scarce capable of bearing, without being reduced to the lowest depths of poverty.

羅馬史是西方世界歷史的基底，此時自然也不能不提。卡爾霍恩指出當羅馬的邊界超越意大利，而延伸過亞德里亞海、阿爾卑斯山和地中海的時候，羅馬（共和國）的自由就消失，取而代之的是帝國的獨裁官。

。。。

又誇了一遍英國政府。

。。。

但是、話鋒一轉，英國這樣做也不是沒有代價的，他評論道：

盡管英格蘭沒有失去自由，也沒有陷入無政府狀態，但我們看到英國人民被沉重的債務和稅收壓垮，有朝一日可能以革命告終。從她的征服和省份財產中獲得的財富可能有助於增加上層階級已經過度增長的財富，但對減輕下層勞動群眾的壓力毫無作用。相反，英格蘭遂行征服和統治異國相關的費用主要來自英國人民的勞動，這種壓力的分量沒有減輕，日復一日得增加了。英國政府給他們帶來了負擔，以至於英國人民要竭盡所有的天分和勤奮，配合大量的資本積累和輔助他們的生產機器，才能勉強免於赤貧的境遇。

Take, for example, Ireland, — her earliest and nearest conquest, — and is it not to this day a cause of heavy expense, and a burden, instead of a source of revenue?

例如英國政府了愛爾蘭——這塊最早征服也是離本土最近的領土，在數個世紀以來一直消耗巨量的開支，成為沉重的負擔，而並未成為英國的富源。

而征服和統治愛爾蘭的資金：

the little she has gained from her numerous conquests and vast provincial possessions, and the heavy burdens which it has imposed upon her people to meet the consequent expenses，

僅僅少量來源於對外征服攫取的微薄利潤，而多數出自加諸於英國人民頭上的沉重負擔。

Nor are the reasons less weighty against incorporating her into the Union. As far as law is concerned, this is easily done. All that is necessary is to establish a territorial government for the several States in Mexico, of which there are upwards of twenty, to appoint governors, judges, and magistrates, and to give to the population a subordinate right of making laws—we defraying the cost of the government. So far as legislation goes, the work will be done; but there would be a great difference between these territorial governments, and those which we have heretofore established within our own limits. These are only the offsets of our own people, or foreigners from the same countries from which our ancestors came. The first settlers in the territories are too few n number to form and support a government of their own, and are under obligation to the Government of the United States for forming one for them, and defraying the expense of maintaining it; knowing, as they do, that when they have sufficient population, they will be permitted to form a constitution for themselves, and be admitted as members of the Union.

就程序而言，將墨西哥併入毫無問題，建立政府、制定法律，並支付這一切的費用。但是這與我們之前建立的領土政府（territorial government ）大不相同（註：美國的“領土政府“用於管理那些已經併入美國，但是還未建立州政府的新領土，歷史上曾有新墨西哥領土、西北領土等）。領土政府只是美國人和其他白人移民（our own people, or foreigners from the same countries from which our ancestors came，我們的人民和祖源國的移民，我這裡直接意譯了）因在新領土上的人數太少，無法組建州政府時的臨時解決辦法，當他們有足夠人數的時候就會被允許組建政府、制定憲法和加入聯邦。

The case will be entirely different with these Mexican territories; when you form them, you must have powerful armies to hold them in subjection, with all the expenses incident to supporting them. You may call them territories, but they would, in reality, be but provinces under another name, and would involve the country in all the difficulties and dangers which I have already shown would result from holding the country in that condition.

但墨西哥的情況完全不同，不僅是組建政府就完事了，還必須以兵威服之、用金錢以維持。或許你可以用領土來稱呼她，但是這不過是換了一個名字的行省。（此處的行省，應該是與有自治政府的州和領土相對，主要靠行政權力統治的、帶有殖民地色彩的地區）

這幾段對墨西哥的描述，著重強調墨西哥與其他美國新領土的異質性，強調這將破壞國家的組織體系的影響，並開始警告美國不要陷入如同愛爾蘭一樣的殖民陷阱。

Ireland has been held in subjection by England for many centuries; — and yet remains hostile, although her people are of a kindred race with the conquerors. The French colony in Canada still entertain hostile feelings towards their conquerors, although living in the midst of them for nearly one hundred years.

緊接著開始闡述融合異質性國土的巨大困難。以愛爾蘭和魁北克舉例說:

愛爾蘭已經做了數個世紀的不列顛附屬國，但是仍然桀驁不馴；前法屬的加拿大殖民地，儘管已經與英國人混居了一百多年，但仍厭惡他們的征服者。

The better class have Castilian blood in their veins, and are of the old Gothic stock—quite equal to the Anglo-Saxons in many respects, and in some superior. Of all the people upon earth, they are the most pertinacious; they hold out longer, and often when there would seem to be no prospect of ever making effectual resistance.

而墨西哥人，將比前兩者更加堅定。至於為啥，是從種族主義黑屁論證極化到了血統種族主義論證：

墨西哥的上層階級的血管裡流著卡斯蒂利亞血，這屬於古老的哥特人血脈——在許多方面與盎格魯-撒克遜人（自然是指美國人）相當，甚至在某些方面還更勝一籌。

這些哥特人是已知世界最頑強的族群，他們在最無望的情況下還能保持抵抗的意志。

（註1：這個判斷應該是受了征服運動的影響，西哥特貴族統領的各個小國被哈里發國壓縮到伊比利亞北部一隅之地，但最後收復了整個半島

註2：卡爾霍恩的祖源來自阿爾斯特-蘇格蘭移民，也就是說他至少有一半的概率是凱爾特人而非盎格魯撒克遜人。）

But suppose this difficulty removed. Suppose their hostility should cease, and they should become desirous of being incorporated into our Union. Ought we to admit them? Are the Mexicans fit to be politically associated with us? Are they fit not only to govern themselves, but for governing us also? Are any of you, Senators, willing that your State should constitute a member of a Union, of which twenty odd Mexican States, more than one-third of the whole, would be a part, the far greater part of the inhabitants of which are pure Indians, not equal in intelligence and elevation of character to the Cherokees, Choctaws, or any of our Southern Indian tribes? We make a great mistake in supposing all people are capable of self-government. Acting under that impression, many are anxious to force free governments on all the people of this continent, and over the world, if they had the power. It has been lately urged in a very respectable quarter, that it is the mission of this country to spread civil and religious liberty over all the globe, and especially over this continent—even by force, if necessary. It is a sad delusion.
None but a people advanced to a high state of moral and intellectual excellence are capable in a civilized condition, of forming and maintaining free governments; and among those who are so far advanced, very few indeed have had the good fortune to form constitutions capable of endurance.

他進一步說：即便墨西哥人沒有任何敵意，並渴望加入我們的聯邦，我們也不能讓其加入。

因為墨西哥人中有1/3是純印第安人（pure Indians），很明顯又是黑屁，他認為總之墨西哥人中至少有1/3：

“並未在道德和智力上達到了組織和維持自由政府的標準。”

“假設所有人都有能力自治，這是一個巨大的錯誤。“

3、卡爾霍恩參議員的觀點總結和政策建議

1. 戰爭是由不道德的理由引發的，但因民意洶湧，並無意阻止之；
2. 經略墨西哥事務會極大加強聯邦政府的事權，且吞併墨西哥南部人口稠密地區會極大擴充其資源，這是各州和議會不願看到的；
3. 墨西哥與美利堅存在極大異質性，無法整合，可以預見激烈的反抗，會浪費生命和金錢，且沒有先例；
4. 無力將美國的自由民主制度在墨西哥復現，原因是”種族智力和道德的根本性差異“。

他對戰爭和領土安排的政策建議也給予前述的理由而成：

The line proposed by me, to which I suppose their reasons were intended to be applied, would be covered in its whole extent—from the Pacific Ocean to the Paso del Norte, on the Rio Grande—by the Gulf of California and the wilderness peopled by hostile tribes of Indians, through which no Mexican force could penetrate. For its entire occupancy and defense, nothing would be required but a few small vessels of war stationed in the gulf, and a single regiment to keep down any resistance from the few inhabitants within.

佔領墨西哥的部分領土，並在此後維持一條防線，以備有利的和平解決條件。

這條防線在哪呢？從太平洋的加里福利亞灣一直延伸到今天德州的埃爾帕索（舊稱北帕索），隨後沿著里奧格蘭德河防禦。（from the Pacific Ocean to the Paso del Norte, on the Rio Grande—by the Gulf of California and the wilderness peopled by hostile tribes of Indians）而絕不佔領墨西哥的人口稠密地區。

很明顯，戰爭的領土解決方案很大程度上與這條線一致。除了登陸韋拉克魯斯進軍墨西哥城以迫降墨西哥之外，戰爭計劃也沒有很大出入。由此可見約翰·C·卡爾霍恩的政治影響力，因此我同時認為，第三部分中總結的觀點正是美國並未全盤吞併墨西哥的理由。

約翰·C·卡爾霍恩的演講原文來自：

The Works of John C. Calhoun. Volume 4 of 6,Gale Ecco, Sabin Americana,2008

参考

1. ^https://en.wikipedia.org/wiki/All_of_Mexico_Movement#cite_note-3
2. ^https://en.wikipedia.org/wiki/Great_Triumvirate
3. ^https://en.wikipedia.org/wiki/John_C._Calhoun#Secretary_of_State
4. ^https://en.wikipedia.org/wiki/Manifest_destiny
5. ^当然不只这一个原因。
6. ^https://en.wikipedia.org/wiki/John_L._O%27Sullivan
7. ^https://en.wikipedia.org/wiki/Identitarian_movement
8. ^https://en.wikipedia.org/wiki/Civil_disobedience