We have argued previously in The Diplomat that China uses aerial incursions into Taiwan’s Air Defense Identification Zone (ADIZ) to signal its displeasure at closer diplomatic ties between Washington and Taipei. While it was anticipated that China would react strongly to U.S. House Speaker Nancy Pelosi’s visit to Taiwan, in defiance of warnings from Beijing, the breadth and depth of Beijing’s fury brought the situation to the brink of another Taiwan Strait crisis.
Pelosi arrived in Taiwan late on August 2. China retaliated by sanctioning natural sand exports to Taiwan and suspending imports of fruits and seafood from the island. Taiwan’s presidential office and various government departments were also subject to cyberattacks. Prior to Pelosi’s arrival, the People’s Liberation Army (PLA) launched a 21-sortie incursion into Taiwan’s ADIZ, with several Chinese aircraft reportedly “squeezing” the median line of the Taiwan Strait before circling back.
As Pelosi arrived in Taipei, China’s Defense Ministry said it would launch “targeted military operations” in response to the speaker’s visit, and the PLA’s Eastern Theater Command announced it would conduct live-fire combat drills in six zones encircling Taiwan from August 4 to 7– which were subsequently extended until August 10. These “combat drills” involved flying drones over the Kinmen islands, firing 11 Dong Feng ballistic missiles over Taiwan (five of which landed in Japan’s Exclusive Economic Zone), carrying out land attack and sea assault drills, island attack drills, and launching large-sortie incursions into Taiwan’s ADIZ. Taiwan blasted China’s drills as a practice for a “blockade.”
On August 5, Beijing further signaled its displeasure with the Pelosi visit by sanctioning the speaker and her immediate family and canceling a range of bilateral exchanges, including the dialogues between the Chinese and U.S. military theaters, the working meetings between the two defense ministries, as well as the consultation mechanism on maritime military safety.
Pelosi’s visit to Taiwan as House speaker is not unprecedented. In 1997, then-Speaker Newt Gingrich also visited the island. Gingrich’s visit, however, occurred in a very different geopolitical epoch. Even though bilateral ties had been strained by the Tiananmen Massacre and the Third Taiwan Strait Crisis, they were nowhere near as fraught as they currently are. Besides, before visiting Taipei Gingrich stopped in Beijing to reassure Chinese leaders that the United States remained committed to a “One China policy” and was against Taiwanese independence.
Given that the U.S. and China are currently not merely in “strategic competition” with one another, but are also trapped in a security dilemma, it is not hard to imagine that Beijing views Pelosi’s visit as further “salami slicing” of the One China policy and strengthening of Taiwan-U.S. diplomatic ties. China was also angered when the Trump administration dispatched Secretary of Health and Human Services Alex Azar to visit Taiwan in August 2020, ostensibly to highlight cooperation on the COVID-19 pandemic. Azar was the highest-ranking U.S. official to visit Taiwan since the U.S. switched diplomatic relations from Taipei to Beijing in 1979. Beijing was further enraged when a month later Undersecretary of State Keith Krach visited Taiwan – the most senior State Department official to visit the island since 1979.
China’s reactions to these high-profile U.S. official visits were harsh and calculated, with Beijing ramping up political and military pressure on Taiwan, holding military drills in the waters surrounding Taiwan, and dispatching large sorties into Taiwan’s southwestern ADIZ and across the median line of the Taiwan Strait.
The Median Line: A Brief History
The median line – running down the center of the Taiwan Strait – was demarcated in 1955 by the then-commander of the U.S. 13th Air Force, General Benjamin Davis, Jr. Its purpose was to clearly delineate the boundary between the two sides and to reduce the risk of another cross-strait crisis. While the status of the median line was never formally codified in an agreement or treaty between China and Taiwan, it was generally adhered to by both sides and served its purpose of keeping their militaries apart, with two brief exceptions in 1999 and 2019.
In July 1999, the PLA dispatched aircraft across the median line after then-President Lee Teng-hui implied the existence of two separate states with his public characterization of China-Taiwan relations as a “special state-to-state” relationship in an interview with Deutsche Welle. In April 2019, two PLA J-11 fighter jets crossed the median line after it was reported that the U.S. had agreed to sell over 60 F-16s to Taiwan.
When Azar met with President Tsai Ing-wen on August 10, 2020, the PLA sent fighter sorties across the median line, the details of which remain scarce. On September 18, 2020, when Krach held a day of closed-door meetings with Taiwanese ministers and dined with Tsai, the PLA dispatched 18 aircraft into Taiwan’s ADIZ, 12 of which crossed the median line. The next day, as Krach attended the memorial service for former President Lee Teng-hui along with Tsai and senior Taiwanese government officials, the PLA launched a 19-sortie incursion into Taiwan’s ADIZ, with 10 fighters crossing the median line.
These incursions demonstrated a new level of intensity, involving multiple intrusions over several days and with PLA aircraft approaching the median line from several different directions and altitudes. The approach served to complicate ROC Air Force’s response, representing a new level of risk and intensity not seen since the Second Taiwan Strait Crisis in 1958. Nevertheless, a sober analysis of these then-unprecedented incursions suggests that they amounted to no more than harassment, posing no serious threat to Taiwan’s security.
A Dangerous New Normal
In contrast, the Chinese retaliation against Pelosi’s visit has resulted in the riskiest and most intense challenge to the Taiwan Strait median line to date. The PLA dispatched 252 sorties into Taiwan’s ADIZ from August 3 to 15; nearly three-fourths of those sorties (185) crossed the median line of the Taiwan Strait.
On August 3, when Pelosi addressed Taiwan’s legislature and met with Tsai, the PLA dispatched 27 sorties into the island’s ADIZ – 22 of which crossed the Taiwan Strait median line before turning around. On August 4, as the PLA’s “unprecedented” military drills encircling Taiwan started, 22 combat aircraft crossed the median line. On August 5, the PLA launched a 49-sortie incursion, with 30 aircraft (24 Su-30s and six J-11s) crossing the median line while another 19 aircraft entered the southwestern portion of the ADIZ. This represented the largest median line violation to date and a particularly sensitive one with the intruding formation appearing as a strike package pointed directly at Taipei (see a map of the incident released by Taiwan’s Ministry of National Defense here).
We argue that the intensity and level of risk associated with the median line violations from August 3 to 5 are the most dangerous incidents in the Taiwan Strait yet, with unparalleled chances for miscalculation.
The high risk of miscalculation was exacerbated by the fact that the distance and flight time from the median line to Taipei is very short: The PLA aircraft could appear above the capital city within minutes, putting additional pressure on Taiwanese pilots and decision-makers. In the following three days, Taiwan’s Ministry of National Defense reported daily median line violations with strike-package-like formations carrying out simulated attacks on high-value targets along the northern portion of the median line, while separate groups conducted air-sea operations in the south with PLA Navy vessels.
Interestingly, since August 9, the median line crossings have adopted a different pattern, with PLA aircraft crossing the line along different points in smaller and disparate groups. On August 9, 16 PLA aircraft (eight Su-30s, four J-16s, and four J-11s) were dispatched along the length of the median line. On August 10, 17 PLA aircraft crossed the median line along different points. On August 11, 11 PLA aircraft (one JH-7, six Su-30s, and four J-11s) crossed the median line again at three different points. August 12 and 13 saw a continuation of this pattern, with PLA aircraft violating the median line at different points, possibly testing ROCAF’s reactions, forcing the air force to scramble quick reaction alerts aircraft from several air bases in response.
The changed incursion pattern also suggests a new PLA approach, with continued harassment effectively nullifying the status quo ante in the Taiwan Strait median line. To be sure, Beijing never formally accepted the existence of the line but had, in practice, respected it for a long time. Nevertheless, the changed pattern of median line violations has lowered the risk of accidental escalation thanks to the change in the intruding formations, now appearing not as strike packages but as disparate groups of fewer aircraft. Despite the change in appearance, the PLA has maintained pressure through sustained frequency of the median line challenges.
With the unprecedented number of median line incursions following Pelosi’s visit, Beijing has drawn a line in the sand (or water) and hopes to demonstrate the repercussions of crossing it to Taipei and Washington. However, the United States appears undaunted, and we may only be at the start of the Fourth Taiwan Strait Crisis.
While Washington has been prudent in not seeking to escalate tensions across the Taiwan Strait, it has also vowed to continue with its transits of the strait and to announce an “ambitious road map” for trade negotiations with Taiwan in the coming days. Also, another congressional delegation has just visited Taiwan, this time led by Senator Ed Markey (D-MA), a member of the Senate Foreign Relations Committee. There was also a report that the U.S. and Taiwan have signed a new deal to maintain the island’s Patriot missile system. Finally, China’s recent actions have solidified bipartisan support on Capitol Hill for the Taiwan Policy Act, which among its many provisions authorizes $4.5 billion in security assistance to Taiwan and designates it a “major non-NATO ally.”
Any of these actions alone would likely enrage Beijing, but the occurrence of all of them will trigger yet another round of vigorous Chinese countermeasures, further escalating tensions and very likely precipitating a full-blown Taiwan Strait crisis. Thus, it is unlikely that we will see a return to the pre-Pelosi visit patterns of ADIZ incursions anytime soon. For all practical purposes, the Taiwan Strait median line no longer exists. What that means, however, is that Beijing will have to engage in even more escalatory and aggressive behaviors to signal its displeasure to Washington, with all its attendant risks and dangers.