The United States military is acutely aware of the possibility that the People's Republic of China on the mainland (the PRC), might try to invade and conquer Taiwan, something that the PRC has repeated threatened to do, although a military conflict with between the Philippines and the PRC in which the U.S. might become embroiled seems more likely in the short term and has resulted in more incidents of low intensity warfare in the last two or three years. I've also explained, elsewhere, why the PRC's reliance on international trade in a wide variety of goods and services to support its economy makes an invasion of Taiwan a much more costly option for it, than a globally unpopular war would be for Russia, whose international exports are dominated by oil and gas, or North Korea, which is very isolated economically from the rest of the world. Further background is available below.
Indeed, the threat of a Chinese invasion of Taiwan is the single largest rhetorical justification used by the U.S. Navy, and to a lesser but still great extent by the U.S. Marine Corps and U.S. Air Force, for U.S. military expenditures.
The U.S. Strategy
The U.S. doesn't have any major military bases in Taiwan, unlike its military bases in Japan, South Korea, Hawaii, Alaska, three U.S. territories in the Pacific, and a smaller U.S. military base in the Philippines (which was once a much larger presence), presumably, in order to formally honor its "One China" policy.
But the U.S. has sold a lot of sophisticated U.S. military equipment to Taiwan, and together with its allies, can marshal considerable naval and air forces in the region.
Basically, the plan is for the U.S., Taiwan, and its allies to direct large numbers of anti-ship missiles and when the opponents are very close, Taiwanese artillery and allied naval gun shells at invading Chinese ships and boats, deployed from land, from surface ships at sea, from every manner of aircraft from long range stealth and conventional bombers, to carrier and land based fighter aircraft (some making the trip with the help of aerial refueling), to maritime patrol aircraft, to C-130 and C-17 military transport planes carrying missile launching cargo, to long range drones, to nuclear attack submarines, with the nuclear attack submarines also launching torpedoes. It would use U.S. satellites, high altitude spy planes, surveillance drones, and U.S. signals intelligence resources to identify targets (as well as any human intelligence resources within China available to the U.S. or its allies). Containerized anti-ship missile batteries will soon make it possible for cargo ships, amphibious transport ships, and merchant ships to also carry and deliver anti-ship missiles with ranges in the hundreds of miles.
Long range bombers, maritime patrol aircraft, C-17s, and fighter aircraft that use aerial refueling tankers, can travel thousands of miles and make the trip in about 12-13 hours from Hawaii. The trip from based in Japan or South Korea or Guam or American Samoa or the Northern Marina Islands would be shorter. Surface ships and submarines not already in the area can take several weeks to arrive, rendering them almost irrelevant in a fast developing naval battle, without a great deal of advance warning from satellites and other intelligence that she China mobilizing.
The aircraft and ships and ground batteries firing anti-ship missiles don't have to get particularly close. The aircraft can stay at high altitudes. Even the shortest range fighter and helicopter carried anti-ship missiles have a range of 18-20 miles. Most have ranges from 100 to 600 miles, and the aircraft can get just within range and turn around if the risk of air defenses is great. Modern torpedoes have a range of about 24 miles, although a longer range provides a target a greater opportunity to evade it.
The U.S. and its allies could deposit of small force of mostly light ground troops in the lead up to an invasion and during an invasion, but for the most part, Taiwan would have to rely on its own troops and reserves, and pre-placed equipment for its ground forces, to repel any Chinese troops that managed to cross the Taiwan strait by sea or by air.
The mission of Taiwan and its allies is easier. It need only destroy or mitigate the harm from incoming ships, aircraft, drones, missiles, and naval gun shells (the Taiwan strait is too wide for cannon artillery or all but the longest range artillery missiles on the mainland to cross) with a mix of anti-ship and anti-aircraft weapons. They don't need to board ships of the People's Liberation Army Navy (PLAN), and don't have to deliver troops or their equipment in an amphibious invasion. PLAN submarines are effective ways to deny access to the ships of Taiwan and its allies and merchant ships bound to Taiwan, but most are fairly short range coastal submarines that have almost no effectiveness against the aircraft of Taiwan and its allies, and pose only a manageable threat to surface warships of Taiwan and its allies that are not in the Taiwan strait or too close to the island of Formosa.
A carrier with F-35C fighter aircraft, for example, need only be close enough for its fighters to fly to the edge of their 700 (non-nautical) mile combat radius which in turn must be within 150 to 700 (non-nautical) miles of the target of their anti-ship missiles. So, the carrier can strike a ship in the Taiwan strait that is 850-1400 miles away from its, for example, from the vicinity of the Northern Marina Islands, or Tokyo, or South Korea, or the southern most islands of the Philippines.
A carrier group at that distance would also have a decent chance of intercepting long range missiles bound towards it from mainland China, and the range of these anti-ship missiles is greater than all but the most potent anti-aircraft missiles in China's arsenal and would have to be timed to strike the aircraft delivering the missiles only just as the aircraft is about to launch its air to ground missiles or is just returning from doing so. And, of course, if an F-35 is hit by a Chinese anti-air missile, only one pilots life, at most, is lost, and there is a decent chance that the pilot could eject and be recovered by a search and rescue team. The number of Chinese ground troops killed every time a Chinese warship or worse yet, a Chinese troop carrying ship, is sunk, would be profoundly greater.
Certainly, Chinese troops that do manage to reach the Taiwanese shore by sea, or by helicopter or transport plane or as paratroops, as elite soldiers in an massive all volunteer military of professional Chinese soldiers are, on average, going to be better trained and more skilled soldiers, than Taiwanese ground troops at the vanguard of a massive but not terribly ready or elite reserve force. But the Taiwanese troops know their territory, have the support of the locals, have been training for this mission and this mission only, are fighting to protect their homes, and will locally outnumber the modest number of Chinese troops that manage to cross the strait at least at first, if the efforts to Taiwan and its allies to destroy incoming troop carrying ships and transport aircraft is reasonably successful.
Also, in an era of Chinese demographics where one child families are the norm, even in this nation of 1.4 billion people, the lives of young men serving as soldiers in the PRC's military are no longer cheap and expendable. And, China has not fought any actual hot conflict in which its any significant number of its soldiers and sailors have lost their lives in the living memory of the vast share of the Chinese people. They haven't had much of a chance to come to see these losses as a necessary price to meet its geopolitical objectives, which it has mostly achieved with trade, aid, and diplomacy.
For all of China's bluster, one can seriously doubt whether China really has the stomach to lose the lives of hundreds of thousands of young men, most of its navy, a substantial share of its air force, and many of its coastal military resources, when it can already extract much of what it wants Taiwan for economically as opposed to culturally or politically, through trade.
China has nuclear weapons, but those too are less potent of a threat in a Taiwan invasion. Using on nuclear weapon on the island of Formosa pretty much defeats the purpose of conquering it and would make it an international pariah. But missile defenses are effective enough that ICBMs aimed to the U.S. or its allies might be completely or almost completely thwarted, with any successes threatening massive nuclear retaliation against it.
The Historical And Geopolitical Context And Background
The island of Formosa is about 100 miles from mainland China across the Taiwan Strait.
A typical naval warship can make the trip in about four hours, a very fast one might make it in two or three hours. A helicopter or slower drone could make it in forty-five minutes or less. A subsonic missile or fighter jet or military transport plane can make the trip in ten to fifteen minutes. A supersonic jet fighter can make the trip in five minutes. A hypersonic missile can make the trip in less than two minutes.
The PRC claims the island of Formosa upon which Taiwan is situated is a rebel province which is part of its territory, along with the strait between Formosa and the mainland, despite the fact that the regime has never had any control or authority on the island, and the fact that no mainland Chinese regime has had any control or authority on the island since 1895. The modern Chinese state dates only to the revolution in China in 1911.
Meanwhile, Taiwan, even more laughably, claims to be the legitimate government in exile of mainland China, a territory it lost any remnant of authority or control over from its inception when its regime retreated there after losing the civil war in China that persisted from the end of World War II in 1945 which left a power vacuum there, until the victory of the Maoists and defeat of the Nationalists in 1949, 75 years ago. The Kuomintang party abandoned its claim to be the sole government of mainland China in 1991 in the same year that it ended "emergency rule".
Imperial China ruled the island of Formosa from 1662 when it ousted the Dutch and large numbers of people from mainland China migrated there, until 1895 when the island was conquered by the Japanese Empire. The Japanese ruled it for half a century until the end of World War II in 1945.
After World War II, there was a civil war in China between the Maoist Communists and the Chinese Nationalist Party led by Chiang Kai-shek. The non-communist Chinese Nationalist Party eventually lost that civil war and relocated to the island of Formosa in a mass migration of its remaining loyalist in 1949 (the same year that the Maoist PRC regimes was declared by Chairman Mao), filling the post-World War II power vacuum caused by the collapse of Imperial Japan's rule there. The following year, in 1950, now 74 years ago, the PRC conquered Tibet.
Chiang Kai-shek ruled Taiwan as a de facto dictator for twenty-six years until 1975, with U.S. backing against expansion of the Communist PRC as part of the Cold War, running the economy on a capitalist model.
The PRC claimed the island as its territory, even though no mainland Chinese government had ruled there since early 1895, and in 1971, after three-quarters of a century in mainland China had no control or authority there, and despite the fact that the PRC regime had never had control or authority there, in 1971, the U.N. recognized the PRC's claim to the island and expelled Taiwan from the U.N. The PRC terminated its diplomatic relationship with Taiwan in 1978. Today, following the U.N.'s lead, only 13 countries, including the U.S., have formal diplomatic ties with Taiwan. The PRC and Taiwan had their first formal talks with each other again in 2014, thirty-six years after breaking off diplomatic relations but have not reestablished diplomatic ties. Per the BBC link below:
Today, only 12 countries (plus the Vatican) officially recognise Taiwan. The US decision to switch diplomatic recognition from Taipei to Beijing in 1979 was the turning point. And a richer, more powerful China exerts pressure so more countries do not recognise Taiwan or lend it support. But America remains the island's strongest ally, sells arms to it and has vowed to help in case of a Chinese attack.
The U.S., however, continued to be a strong ally to Taiwan and its military guaranteed its independence from the PRC, and under its influence, Taiwan eventually reformed itself, carrying out land reform to address the feudal era inequalities that led to the Maoist revolution on the mainland, instituting universal public education, modernizing its agricultural and industrial economies, and finally, step by step becoming a democracy. Martial law was lifted in 1987 after 38 years. Four years later in 1991, four decades of "emergency rule" was ended. And, five years after that in 1996, Taiwan had its first direct Presidential election, which the Kuomintang party, the successor to the original Chinese Nationalist Party that had controlled Taiwan for forty-seven years since 1949, won.
The uncontested rule of Chiang Kai-shek's dominant Kuomintang party finally ended in the year 2000, when the leader of the pro-independence Democratic Progressive Party won the Presidential election, only for the Kuomintang party to regain the Presidency from 2006 to 2016, when the Democratic Progressive Party regained the Presidency, in part, over concerns that the Kuomintang party was to friendly with China and might jeopardize Taiwan's independence. The Democratic Progressive Party still holds the Presidency today. China has gradually stepped up its saber rattling towards Taiwan since the Kuomintang Party lost the Presidency in 2016.
Despite a lack of formal diplomatic relations, 21% of Taiwan's imports are from the PRC and 26% of its exports are to the PRC.
About 70% of the Taiwanese people are Han Chinese, another 25% or so are from another Southern mainland Chinese ethnicity, about 2-3% of the Taiwanese people are indigenous Formosans who speak sixteen different languages once of which is the ancestral language of the Austronesian family of languages spoken from Easter Island and Oceania, to Southeast Asia, to Madagascar, with a small percentage of people of other ancestries. Mandarin Chinese, and two other Chinese topolects (one of which has several dialects) are the predominant languages of Taiwan. But even Chinese languages like Mandarin which are present in both Taiwan and the mainland have developed distinct Taiwanese accents that are perhaps as distinct from their mainland counterparts as American and Canadian English dialects, in their spoken versions, in the non-logographic written versions of them, and in subtleties of meaning and pronunciation of their shared Chinese characters.
Over the last thirty years or so, however, the people of Taiwan have increasingly come to identify themselves as Taiwanese, or as both Taiwanese and Chinese. About two-thirds identify as Taiwanese only. Almost a third identify as both, and only one or two percent now identify only as Chinese.
Taiwan's religious makeup reflects the pre-Maoist religious mix of China, with 42% adhering to Chinese folk religion (a close cousin of Japanese Shinto practice), 27% identifying primarily as Buddhist, 13% identifying as Daoist, 7% identifying with East Asian "new religions", 6% as Christian, and the remainder as non-religious agnostics, although these religious movements are not nearly so mutually exclusive as Western religious denominations and sects.
Taiwan controls a territory of about 13,900 square miles, while the PRC controls about 3.7 million square miles, which is about 2660 times as large.
Critically, the PRC of today is not the PRC of 1949. While the PRC doesn't adhere fully to the extreme version of capitalism found in the United States and has high levels of state involvement in the economy, its record economic growth for many decades has been made possible only through market based economic reforms, soft recognition of property and contract rights, and sufficient openness towards ideas from the world outside of China to allow it to gain the scientific and technological knowledge necessary for it to rapidly catch up to the developed world.
The assimilation of Hong Kong into China has meant even more growing pains for both sides.
China is still astoundingly authoritarian, but it is also not the raw, unpredictable cauldron of violence that it experienced in the 1970s during the Cultural Revolution.
Despite being nominally communist, China has its fair share of billionaires and there is a great deal of overlap between its political elites and its economic elites. In other words, China's rules are also among the very wealthiest people in the entire country, which makes a return to an extremely leveling brand of communism that eats the rich unlike to recur there, even if it is quite a dangerous thing to be a billionaire or centi-millionaire in China that can lead to your untimely demise in a usually not officially acknowledged manner if the cross the wrong people or offend the sensibilities of leaders in the Chinese Communist Party.
So far, China has liberalized economically in a gradual manner, rather than all at once as the Soviet Union did in what turned out to be a chaotic and sudden mess that transformed the country from Soviet style communism or crony capitalism run by oligarchs in less than a quarter of a century, with intense societal and governmental pain along the way. This lesson schools Chinese Communist Party leaders to be cautious in their reforms, and had discouraged a relaxation of its authoritarian political model.
But the expectations of continuous fast economic growth that they have developed for themselves puts pressure on them to adopt policies that work to continue that as much as possible and at some point, China's authoritarian rule will have to be relaxed to sustain that, particularly as China starts to have to rely on new innovations of its own, rather than copying proven global economic and technological models to achieve new economic growth. Also, non-economic freedom is, to some extent, one of the luxuries that people in economically prosperous societies crave and desire. The more affluent the Chinese people become, the more they are going to be willing to face significant personal risk and sacrifice and economic resources to escape authoritarian rule. And, there are enough wealthy Chinese people who have traveled abroad to less authoritarian counties, or who have access to less censored international media, that they can know that it is possible to leave in a freer and more democratic world (and the people of Hong Kong have demonstrated that this can work even for ethnically and culturally Chinese people), that it is an enjoyable and desirable intangible luxury to have, and that there are ways of achieving and sustaining it that they can learn and copy as they did less political foreign technologies. It isn't clear how smooth or rocky the path to that end will be, and in the near term, transitioning from China level authoritarianism to Singapore level authoritarianism, or something like it, may be an intermediate step. But it is hard to see a trajectory in which China becomes more insular and authoritarian, rather than less so, in over the next several decades.
This is all to say, then, that it an invasion of Taiwan can be discouraged for a sufficiently long period of time, that eventually mainland China may eventually catch up with Taiwan (which has only enjoyed more or less full democracy and social freedoms for thirty years or so itself), at which point a merger of the PRC and Taiwan might not be so problematic anymore.
Military Capabilities
Taiwan is quite militarized, with 169 thousand active duty military personnel, 1,657 thousand reserve troops, and a defense budget of $16.2 billion. But this is dwarfed by the PRC's 2,035 thousand active duty military personnel, 650 thousand reserve troops, and $242.4 billion USD defense budget. Taiwan has 26 surface warships of frigate class or larger and 4 military submarines and many smaller naval and coast guard vessels. China has 92 surface warships of frigate class or larger and 59 military submarines and many smaller naval and coast guard vessels and is expanding its fleet rapidly. Taiwan's air force has 405 jet fighters. China has more than 1,628 jet fighters. Taiwan has 650 tanks. China has 4,800 tanks.
Unlike the United States and Russia, which have large "blue sea Navies", China's ships rarely venture more than 400 miles from its Pacific Coast (although China has deployed as many as a dozen naval ships to suppress pirates in the Indian Ocean right up to the Persian Gulf and Red Sea, and has an ample merchant and fishing fleet that is sometimes pressed into paramilitary service), and Taiwan's navy stays even closer to home.