Is the U.S. immune to invasion?
對於敵人的入侵，美國是否可以完全免疫？
Quora讀者的評論：
Sam Hopper, works at The High School Experience
A continental invasion of the US would be nearly impossible. You have a nation with perfect natural borders in the form of entire oceans on either side. Then you have to defeat the biggest and most technologically advance navy and air force in the world (by a mile) just to get to the shores. And thats only if the US's force immense global force projection capability doesnt destroy the invading nation before it occurs. Then if by a mere miracle they beat the military and get to the US coast, they have to deal with 100 million privately owned firearms carried by an enormous civilian insurgency, many of which have been day-dreaming about such a scenario forever.
The US is big. Attacking a country that large is a logistics nightmare - it's similar to going through Siberia to conquer Russia. You're going to get spread thin, and then you're going to starve and get routed.
The US has a massive amount of force in places that could be invaded. Notice how most of the bases are in coastal areas? (Georgia, North Carolina, Virginia, California, etc) They're there for a reason - an attack is not going to come from Kansas. So, not only do they have a lot of firepower, it's already in the best spot for an invasion.
The United States has one of the most massive armed forces, so therefore a type of standard military attack would be ineffective. The only possible way the cripple the United States would be unorthodox.
Unorthodox methods such as super contagions, nuclear weapons, aliens, cyber attacks, the Illuminati, or Mine craft..
"America will never be destroyed from the outside. If we falter and lose our freedoms, it will be because we destroyed ourselves." -Abraham Lincoln
入侵美國大陸幾乎是不可能的事。你們國家有著完美的自然國界，國土的每一邊都有一整片的海洋。敵方還必須擊敗世界上規模最大、技術最先進的海軍和空軍，才能到達海岸。只有在美國強大的全球軍力投射能力沒能在入侵前摧毀這個國家的情況下才可能做到。如果發生了奇蹟，他們擊敗了美國，到達了美國海岸，他們還必須面對攜帶了一億支私人槍支的龐大的平民叛亂分子，其中許多人一直夢想著這樣的場景。
美國地域寬廣。襲擊一個這麼大的國家對於軍隊後勤來說簡直就是噩夢——就像穿越西伯利亞去征服俄羅斯一樣。你們的戰線會拉得很長，忍飢挨餓，被打得潰不成軍。
美國在可能被入侵的地區擁有大量的軍事力量。注意到大部分基地都設在沿海地區嗎?(喬治亞州、北卡羅來納州、弗吉尼亞州、加利福尼亞州等)他們在那裡設立基地是有原因的——襲擊不會來自堪薩斯州。所以，他們不僅擁有強大的火力，而且在應對入侵的最佳位置做好了防備。
美國擁有最強大的武裝力量之一，因此常規軍事攻擊無法攻破美國的防線。唯一可能使美國陷入癱瘓的方法只能是非常規做法。
非常規做法，有如超級傳染性，核武器，外星人，網絡攻擊，光照派或地雷。
“美國永遠不會從外部被摧毀。如果我們動搖並失去自由，那隻能是我們毀滅了自己。”—亞伯拉罕林肯。
James Ware, Strong interest in History
No, the United States at its current state is not impossible to invade, but it is rather difficult. Anyone could invade the US at the moment. Just sail on by in the name of friendship then put boots on the ground and declare war. They would be admittedly wiped off the face of the Earth, but it was an invasion. Almost as successful as Napoleon’s in Russia.
The US has the advantage of being in the New World. We have the largest oceans to the West and East making an amphibious invasion a lot harder than most places. Sure there are islands one could use, but a significant movement of ships and men would be visible and will give us time to prepare. Also compared to the Old World, we do not have long lasting hostilities with our neighbors. Sure things weren’t like they were a few centuries ago (War of 1812, Mexican-American War), but currently, the US, Canada, and Mexico have been on good terms for quite some time.
不，美國目前的狀態並非不可能入侵，但是相當困難。現在任何人都可以入侵美國。以友誼的名義揚帆遠航，然後踏上美國土地並宣戰。無可否認，他們將從地球上消失，但這是一種入侵。幾乎和拿破崙在俄國一樣成功。
美國的優勢在於身處新世界。我們的西部和東部有最大的海洋，這使得通過水陸入侵比大多數地方要困難得多。當然有些島嶼是可以利用的，但是大量的船隻和人員的移動是很顯眼的，這將給我們時間來做應對準備。與舊世界相比，我們與鄰國之間沒有長期的敵對行動。當然，現在跟幾個世紀前不同了(1812年戰爭，美墨戰爭)，但目前，美國、加拿大和墨西哥的友好關係已經持續一段時間了。
Chris Briere, Born and Raised
The US is definitely invadable, at least for a nation with nukes.
Step 1: Detonate one or two high yield nuclear war heads high in the atmosphere above the United States. The resulting EMP will knockout a large amount of Military equipment destroying nearly all civilian electronics.
Step 2: While the US is trying to stop the nation from descending into anarchy as the entirety of the economy (nearly every car, refrigerator, etc.) grinds to a halt, send several thousand well trained Guerrilla fighters across the Canadian and Mexican Boarders armed with large amounts of C-4 and other explosives. Have these operate in independent terrorist cells with each group targeted to take down a series of strategic pieces of infrastructure, i.e. bridges. This will ripe the Interstate Highway System to Shreds.
Step 3: Wait a couple months for most of the population to die to pillaging and starvation, then mark in with what ever army you want. At this point the American people will likely welcome you for bringing stability to a war torn nation.
P.S. You'll have to keep the rest of the US allies busy in order for this to really work. If you have more nukes then detonating a couple above their nations will probably do the trick.
美國絕對是能夠入侵的，至少對於一個擁有核武器的國家來說是如此。
步驟1：在美國上空的高空引爆一兩次高當量核彈。由此產生的電磁脈衝將摧毀大量軍用設備，摧毀幾乎所有民用電子設備。
步驟2：等美國試圖阻止這個國家陷入無政府狀態時，整體經濟嘎然而止，派遣數千名訓練有素、裝備了大量C-4和其他炸藥的游擊戰士前往加拿大和墨西哥邊境。讓他們獨立進行恐怖活動，意在摧毀一系列戰略性的基礎設施，如橋樑等。這將使州際公路系統趨於癱瘓。
第三步：等待幾個月，等待大多數人死於掠奪和飢餓，然後派出軍隊。在這一點上，美國人民可能會歡迎你為這個飽受戰爭蹂躪的國家帶來穩定的希望。
附註：你必須讓美國的盟友雜事纏身，這樣才能真正發揮作用。如果你有更多的核武器，那麼在他們的國家上空引爆幾枚核彈可能就會奏效。
Khalid Elhassan
Only Canada and Mexico share a land border with the US, and both their militaries are negligible. Even if all the militaries of the Western Hemisphere (the only countries that can theoretically reach the US borders overland without having to put to sea) combined, their combined might would be too negligible.
Everybody else would have to come by sea, and it's hard to come by sea when the US Navy on its own is stronger than all the navies of the rest of the world put together.
只有加拿大和墨西哥與美國接壤，兩國的軍事力量微不足道。即使西半球的所有軍隊(理論上只有西半球的國家可以通過陸路到達美國邊境)加在一起，軍事實力也可能微不足道。
其他國家都必須通過水路才能進入美國，但鑑於美國海軍自身的力量超過世界其他國家海軍力量的總和，從水路進攻難度很高。
So for all practical purposes, at present (2016) the US is uninvadable.
因此，就所有實際目的而言，目前(2016年)美國是不可侵犯的。
Angelo Luna, studied at Santa Rosa Junior College
if you don’t care about civilian lives and soldiers lives, probably. the problem with invading the US is that there are many trained small militia groups that have AR-15’s in the US or some other legal weapons depending the state you plan to inveade. if a country succeeds in taking large parts of a state, the militia will be ready if the army isn’t coming. most of the citizens in the US are sometimes armed with pistols or semiautomatic rifles, with bullets that probably can pierce armor. the police stations across the US has some form of military grade items like weapons and armor that the police can probably give out to the militias that are fighting the enemy. the US militia obviously is small, so they’ll do guerrilla tactics to slow down the enemies advance or halt them to give the army enough time to send the soldiers to fight them.
如果你不關心平民和士兵的生命，也許吧。入侵美國的問題在於，許多訓練有素的小型民兵組織在美國擁有AR-15或其他合法武器，這取決於你計劃入侵哪個州。如果一個國家成功佔領了一個州的大部分地區，如果軍方還沒到來，民兵就會先做好準備。在美國，大多數公民持有手槍或半自動步槍，子彈能夠穿透盔甲。美國各地的警察局都有一些軍事級別的軍防用品，比如武器和盔甲，警察可能會把這些物品分發給與敵人作戰的民兵。很明顯，美國民兵規模很小，所以他們會用游擊戰術來減緩敵人的進攻，或者阻撓他們，給軍隊足夠的時間來派遣士兵與他們作戰。
if a country plans on invading the US, they should attack any democratic liberal state, like california or NYC since those states have very strict gun control where you probably can’t buy an ar-15 and where most of the citizens will have a hard time getting them. also, they’re the land of the anti gun where few people have guns, so guerrilla warfare will be minimal, making the enemy have an easy time invading.
如果一個國家計劃入侵美國，他們應該攻擊那些皿煮自由的州，比如加利福尼亞州或紐約市，因為這些州有非常嚴格的槍支管制，你可能買不到ar-15，大多數公民很難得到它們。此外，他們是反槍支的地區，那裡很少人擁有槍支，所以游擊戰會很少，敵人就贏得了入侵的時間。
Paul Knierim
Rather than write about US military defenses, I’ll take this question as if the USA had a $0 military budget. In such a case, Hawaii becomes vulnerable. Alaska might fall to a summer invasion too but would be very hard to keep an occupation force in against winter insurgency. Outlying non-state territories like Puerto Rico could fall as well.
The contiguous 48 states, however, are essentially immune to invasion as long as they don’t horribly antagonize Canada or Mexico — even if the USA drops out of NATO and alienates all other allies. Consider that the world’s most powerful military has been unable to fully subdue Afghanistan and Iraq with decades of effort — then consider the relative size and population of the USA and how much bigger a challenge that becomes.
Then consider the need for a land route (even poverty-stricken Iraq and Afghanistan required land routes, landing all your troops by boat is impracticable for invading a very large nation — that was the worry about invading relatively small Japan in WWII as well). This means you have to invade either Canada (the world’s second largest country) or Mexico (a county of 127,000,000 people) just to reach the USA. Canada has no land route into it, so you’re probably trying to invade Mexico with the cooperation of Guatemala… across a relatively tiny border from which you’ll have to fight more than a thousand miles through dense populations. You’ll be very lucky if you still have any sort of army by the time you reach the USA border — realistically the only country Mexico is geographically vulnerable to is the USA.
我不想寫美國的軍事國防，我會給這個問題設立一個前提，就是美國的軍事預算只有0美元。在這種情況下，夏威夷就岌岌可危了。阿拉斯加可能也會在夏季遭到入侵，但要留一支部隊來對付冬季的叛亂活動則非常困難。像波多黎各這樣的非國家領土也可能會淪陷。
然而，只要不跟加拿大或墨西哥發生重大摩擦，其餘48個州基本上不容易遭受入侵——即使美國退出北約，疏遠所有其他盟國也一樣。考慮到世界上最強大的軍隊無法通過幾十年的努力完全征服阿富汗和伊拉克，再考慮一下美國的相對規模和人口，這將會是一個非常大的挑戰。
然後再考慮陸上路線的需要(即使是貧窮的伊拉克和阿富汗也需要陸上路線，讓所有的軍隊坐船登陸是不可能入侵一個大國的)。這意味著你必須入侵加拿大(世界第二大國家)或墨西哥(一個擁有1.27億人口的國家)才能到達美國。加拿大沒有陸路進入墨西哥，所以你可能試圖在危地馬拉的合作下入侵墨西哥，你將不得不在人口密集的地區與墨西哥作戰。如果你到達美國邊境時還有兵力，那就非常幸運了——實際上，在地理上墨西哥唯一易受攻擊的國家只有美國。
There is one and only one plausible way to invade the USA (nuking it into oblivion doesn’t count as invasion, that’s obliteration): make the population of the USA believe you’ll provide them a better government than what they’ve got. If you’re welcomed as liberators by most of the populace, then you have the allies you need to take on small insurgencies.
Outside of Hawaii and possibly Alaska, the USA is ironically probably the nation with the least need for defense spending in the whole world. And yet the nation that spends so much more than any other and in the process makes itself less safe, putting its soldiers in vulnerable places and meddling with other governments to create instability that breeds international terrorism.
入侵美國的方法只有一個，也是唯一可行的方法(用核武器摧毀美國並不算入侵，那是毀滅)：讓美國人民相信，你將為他們提供一個比現在更好的政府。如果你作為解放者受到大多數民眾的歡迎，那麼你就有了盟友來對付小型叛亂。
具有諷刺意味的是，除了夏威夷和阿拉斯加，美國可能是世界上國防開支需求最低的國家。但這個國家的軍費開支卻比其他任何國家都要多，而且在這個過程中，它讓自己變得更不安全了，把自己的士兵派往易受攻擊的地方，並干預其他政府，製造不穩定局面，滋生國際恐怖主義。
Steven Helferich, Born and raised in the USA
From a conventional military standpoint? For all intents and purposes, yes. To successfully invade the United States, you'd need a blue water navy capable of defeating outright the US navy while also carrying an invasion force to North America.
I know some people might argue that this is not a requirement, but you need to think beyond just getting the troops to American soil. You will also need to maintain supply lines throughout the invasion. This is hard enough even when you're not trying to ship men and supplies 3,000 miles across an ocean full of hostile enemy vessels. Even at the end of WWII, when the US had undisputed control of the Pacific, it still balked at going for an all-out invasion of a much smaller and weaker opponent due to many of these issues. It took 4 years of constant warfare just to gain control of vital island territory to support military activity. I think it's simply impossible to maintain a fighting force in North America without directly defeating the US navy and taking naval superiority. This is obviously a daunting task that no single nation is capable of achieving currently. Even combining all the world's major navies may still not be enough, especially considering you'd have to organize a dozen different countries, some who hate each other, and many of which have no modern experience in conducting warfare.
從傳統軍事的角度來看？是的。要想成功入侵美國，你需要一支深藍海軍，才能夠徹底擊敗美國海軍，同時還要向北美派遣一支入侵部隊。
我知道有些人可能會說這不是必要條件，但你需要考慮的不僅僅是讓軍隊進入美國本土。在整個入侵過程中，你還需要維護補給線。即使你不想在充滿敵方船隻的海洋中運送人員和物資3000英里，這也非常困難。即使在第二次世界大戰結束時，當美國無可爭議地控制太平洋時，但由於許多這樣的問題，美國仍不願對一個弱小得多的對手發動全面入侵。為了控制重要的島嶼領土以支持軍事活動，美國打了一場持續了4年的戰爭。我認為，不直接擊敗美國海軍並取得海軍優勢，在北美維持一支戰鬥力量是不可能的。這顯然是一項艱鉅的任務，目前沒有一個國家能夠完成。即使把世界上所有的主要海軍結合起來也可能不夠，特別是你必須組織十幾個不同的國家，其中一些國家彼此仇恨，而且許多國家在作戰方面沒有現代經驗。
There are simply too many physical and geographical advantages to the US position as well. The US has a desert to the south, mountains throughout, and a cold biome along its northern border. Invading from either Mexico or Canada would also require one of those two to break their alliances with the US, which is also unlikely. Invading the US directly along its coastline is the most geographically viable, but as I said, it brings up the issue of beating the US navy and establishing supply lines.
I've read some of the other answers on here bringing up unconventional means like EMP's. I can think of a few others like biological warfare, but the issue is that none of these deals with the US navy that is sailing around the oceans. Even if you deal damage to the general population, invasion still relies on you being able to put boots on the ground and keep them there. You can't do that while the US military is active.
I suppose if literally the entire world united against the United States, then it would be possible to invade the US simply because it would be overwhelmed. However, I'm not sure this is really the kind of answer you are looking for. I put this one up there with "Meteor strikes the Pentagon" and "entire US population suddenly falls into mysterious coma". Another might be bribing enough US admirals that you gain de facto control of the US navy in the case of a conflict. This way, you gain control of the seas from the get-go. Invasion would be much easier in this case, although occupation would still be a problem. These are all possible scenarios, but they are so unlikely that it's not useful to take them seriously.
Maybe in 50 years if the US declines and states like China and India develop navies that can go toe-to-toe with the US, I might change my answer. Until then, it'd require such an unlikely combination of factors that I just don't think you could seriously attempt it outside of a sci-fi novel.
美國的地理和地理優勢實在是太多了。美國南部有沙漠，山脈遍佈，北部邊境有寒冷的生物群落。從墨西哥或加拿大入侵美國，就需要這兩個國家中的一個斷絕與美國的聯盟，這也是不太可能實現的。從地理上講，直接沿著海岸線入侵美國是最可行的，但正如我所說，它也面臨著擊敗美國海軍和建立補給線的問題。
我看到一些其他的答案，提出了採用非傳統的方法，如電磁脈衝。我能想到其他一些類似於生物戰的例子，但問題是，這些方法都繞不開正在海上航行的美國海軍。即使你對普通民眾造成了傷害，入侵仍然依賴於你是否能夠派遣地面部隊並將軍隊留在那裡。美國軍隊還在活動的時候，你是無法做到的。
我想，如果整個世界真的聯合起來反對美國，那麼就有可能入侵美國，因為它會被擊潰。然而，我不確定這是不是你想要的答案。我把這張圖片放在上面，上面寫著“流星撞擊五角大樓”和“整個美國人口突然陷入神秘的昏迷”。另一種可能是賄賂足夠多的美國海軍將領，以便在發生衝突時獲得美國海軍的實際控制權。這樣，你從一開始就能控制美國海軍。在這種情況下，入侵會容易得多，儘管佔領仍然是個問題。這些都是可能發生的情況，但是它們太不可能了，所以沒有太認真。
或許50年後，如果美國衰落，中國和印度等國的海軍能夠與美國正面交鋒，我可能會改變我的答案。在那之前，入侵美國需要極其不可能的因素組合，我認為除了科幻小說，你就不要當真了。
Kevin Stern, B.S. Computer Information Systems (1997)
Nope. It’s very hard to do. Assuming our military is somehow unable to stop them from reaching our shores, resistance would be fast because our military still kicks butt. And they’ll have the people’s help (for once, so many armed citizens will be a good thing), So the invaders would be quickly kicked out. Damage would be minimal.
It’s why most US is invaded stories have our enemies using EMPs to knock out our technology, or super viruses (which mostly don’t exist) to kill us. Even then, with a virus, the goal is to kill us, not invade. That only leaves technology attack. And we don’t actually need it. Our guns work without technology. and sticks and stone do indeed break bones. In short, even with crippled technology, we’d still put up quite the fight. nay invader would be hard pressed to conquer us. Also, they might not have any tech to sue themselves (depending how long lasting a EMP blast lasts). if they do, rest assured, sooner or later we’d commandeer their tech, and sue their own vehicles, computers, etc against them. Yes it’d take longer, but we’d win. All those dystopias about no tech, and we turn one each other, ends pretty quickly when we see a common enemy.
This is why nobody’s ever tried it. It’s a losing scenario for any invader. Either we stop them from arriving, or we quickly kick them out. Anything big like disabling us, gets the rest of the world antsy. So they’ll protect themselves from a future attack. Fighting on two fronts is never easy.
不。這很難做到。假設我們的軍隊無法阻止他們到達我們的海岸，國防抵抗將會很快展開，因為我們的軍隊仍然在戰鬥。他們將得到人民的協助(這麼看的話，武裝公民是一件好事)，因此入侵者將很快被趕走。損失微乎其微。
這就是為什麼大多數入侵美國的版本中，都有敵人使用電磁脈衝來摧毀我們的技術，或者使用超級病毒(大多數並不存在)來殺死我們的說法。即使這樣，病毒的目標是殺死我們，而不是入侵。剩下的只有技術攻擊了。實際上我們並不需要它。我們的槍支在沒有技術的情況下也能發揮效力。棍棒和石頭確實能折斷骨頭。簡而言之，即使是在技術癱瘓的情況下，我們仍然會進行相當激烈的鬥爭。不，入侵者很難征服我們。
這就是為什麼沒有人嘗試入侵美國的原因。對任何入侵者來說，這都是註定失敗的局面。我們要麼在他們抵達之前就攔截住他們，要麼就把他們徹底打跑。搞殘我們美國這樣的大事，會讓世界其他地方坐立不安。所以他們會保護自己免受未來的攻擊。搞兩線作戰從來都並非易事。
Dan Holliday, lived in The United States of America
Unless you have one of these:
除非遇到這樣的情況：
It's essentially un-invadable. There just isn't a collection of nations that can overcome the really vast oceans, the US Navy, Marine Corps, Army, and Air Force and, well, not to be forgotten, several thousand nuclear warheads.
Let's say all of humanity outside North America decided to invade. In WWII, two seafaring (the *most* seafaring) nations effected an amphibian invasion just several dozen miles away from southern England. It took thousands of boats. To undertake a similar invasion, they'd either have to cross into Alaska and fight their way down from there. The land between Alaska and Canada/USA proper is horrific. Then they'd be getting nuked, bombed and shelled all along the way. Up from South America? Go ahead. Cross the mountains and jungles. The land connecting North and South America is also horrific. Then there'd be the aforementioned shelling, bombing, nuking along the way.
It's not that the US isn't invadable. It is. It's just this: Would it be worth it? Would it be worth killing the millions of people in the US while losing hundreds of millions of young people? Would the sacrifice of youth from India, Russia, China, Europe be worth it? The answer is no. It wouldn't. The world saw the ugliest war in history. It took a long hard look at itself. There hasn't been a global war or a fully, mechanized war between industrialized nations since then.
根本而言，美國是不可入侵的。沒有一個國家能夠征服浩瀚的海洋，美國海軍，海軍陸戰隊，陸軍，空軍，還有，別忘了，幾千枚核彈頭。
假設北美以外的所有國家都決定入侵。在第二次世界大戰中，兩個海上大國在離英格蘭南部幾十英里的地方發動了兩棲入侵。動用了成千上萬艘船。為了進行類似的入侵，他們要麼必須穿越阿拉斯加，然後一路攻打。阿拉斯加和加拿大/美國之間的土地是可怕的。他們會一路遭到核轟炸和炮擊。從南美入侵？儘管去吧。穿越高山和叢林。連接北美和南美的土地也是可怕的。然後還是會遭遇前面提到的炮擊、轟炸和核攻擊。
當然，美國並非不可侵犯。它一樣會被入侵，只是這樣值得嗎？在美國殺死數百萬人，讓數億年輕人喪命，值得嗎？來自印度、俄羅斯、中國和歐洲的年輕人的犧牲值得嗎？答案是否定的。不值得。世界見證了歷史上最醜陋的戰爭。它花了很長時間來仔細審視自己。從那時起，工業化國家之間就沒有爆發過全球性的戰爭，也沒有發生過完全機械化的戰爭。
