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Chinese intrusions in Taiwan's ADIZ, Ko Wen-je and death of the Davis Line

China changing status quo across Taiwan Strait, flouting Davis Line prime example

Chinese J-16 fighter plane. (MND photo)

Chinese J-16 fighter plane. (MND photo)

TAICHUNG (Taiwan News) — The Davis Line has surprisingly been in the news recently. Also referred to as the “median line,” “middle line” and “center line,” it refers to an imaginary air force “do not cross” line that runs right through the middle of the Taiwan Strait between Taiwan and China.

While it never had official status, it was observed by both Taiwan and China starting in the 1950s and effectively enforced by the United States: Neither side’s air force shall broach this line.

It was named after the American war hero Brigadier General Benjamin Davis, then commander of Task Force 13 in Taipei, who had previously served as commander of the World War II Tuskegee Airmen and was the first African-American brigadier general in the U.S. Air Force.

Map of incursions on June 21 with the rectangle showing Taiwan's ADIZ (though the portion over China is usually ignored) and the strait line in the Taiwan Strait showing the Davis Line

It formed one of the core elements of the much-discussed status quo in Taiwan-China relations, and was respected by the Chinese Communist Party (CCP) air force, the People’s Liberation Army Air Force (PLAAF) until 1999. Yes, you read that right, the People’s Republic of China (PRC) has no military, it is actually the CCP’s armed wing and exists to keep the party in power, not protect the nation or state.

Still, the PLAAF flouted the Davis Line sparingly, only crossing it on two more occasions in 2011 and 2019. While crossing the median line still remains uncommon, starting in August 2020, incursions into Taiwan's air defense identification zone (ADIZ) really ramped up.

Thugs with baseball bats

Technically, crossing the median line is not illegal under international law. As Zhu Fenglian (朱鳳蓮), a spokesperson for China’s Taiwan Affairs Office (TAO) put it: “The so-called median line does not exist.”

Though disappointingly she did not give General Davis the credit he is due, she is right: It was a made-up tacit agreement. The same could be said for the 1992 consensus, though I doubt she would agree.

In fact, intrusions into Taiwan’s ADIZ are not illegal under international law either. An ADIZ is not the same as a country’s air space (violating that is illegal under international law), but rather a zone extending beyond it to identify potentially hostile aircraft, a courtesy the PLAAF overtly and insultingly ignores.

While not illegal, it is extremely belligerent, threatening, bullying, and dangerous. It’s like being in a public parking lot surrounded by thugs swinging baseball bats inches from your face, but never actually connecting.

Until it does.

This is highly risky behavior, and the potential for accidents between PLAAF aircraft and the fighters scrambled to meet them by Taiwan’s air force is a very real possibility. It is also “gray zone warfare,” which is warfare conducted by other means short of actual shots being fired.

Upending status quo

It is a clear move by China to change the status quo in the Taiwan Strait — which China blames on everyone else — and they recently significantly upped the ante by claiming the entire Taiwan Strait, including Taiwan’s airspace, as its own. There is absolutely no legal justification for this claim, and theoretically could lead to a clash between Taiwanese, American or other country’s military vessels operating in internationally-recognized waters and the People’s Liberation Army Navy (PLAN) or coast guard (which recently was given more dangerous powers).

Unfortunately, these incursions serve CCP purposes well on many fronts; militarily, psychologically, diplomatically, and for propaganda for domestic consumption. Remember, the CCP considers itself at war with Taiwan and has no interest in peace, just not actual kinetic combat (for now at least).

The first clear purpose of their incursions was diplomatic messaging, and the very first incursion in 1999 was after President Lee Tung-hui (李登輝) said Taiwan-China relations were “state-to-state.” The first August 2020 incident that kicked off the flood of incursions was one day after U.S. Health and Human Services Secretary Alex Azar landed in Taiwan, who at the time was the highest-ranking U.S. official to visit Taiwan.

The Taiwanese military has stated that they believe part of the reason for the incursions is to affect public morale in Taiwan.

Incursions serve military

It is also useful for domestic Chinese audiences. It demonstrates Chinese strength to the public, and likely boosts morale in the military.

They also serve multiple military purposes. They are clearly using them for training, which is especially useful to conduct in airspace where they could potentially initiate conflict.

Most of the incursions take place in the southwest corner of the ADIZ, just to the northeast of Taiwan’s Dongsha Islands and in the Bashi Channel, and often include anti-submarine and surveillance aircraft. The channel is an important route out for the PLAAF and PLAN, as well as a route in if a war breaks out for the U.S. and other navies.

The Chinese may also be eyeing taking the Dongsha Islands, which are in a strategic position. Dongsha is the blue dot marked on the map above.

Another useful military purpose is to wear down Taiwan’s Air Force, as well as test its capabilities and response times. Taiwan can not stand by and let enemy aircraft potentially fly into its airspace, and sends out jets to confront them.

However, with the PLAAF’s superior number of planes, this is causing strain on the much smaller Taiwan air force’s pilots and wear and tear on the planes. By October 2020, this cost the air force over US$1 billion (NT$29.93 billion), or nearly 9% of the entire military budget.

Play the same game

In spite of all the incursions, President Tsai Ing-wen (蔡英文) has very carefully avoided sending Taiwan’s Air Force across the Davis Line. By continuing to honor the previous tacit understanding, she in making it clear that Taiwan is working to uphold the status quo, underscoring that it is China who is the aggressor that has changed it.

Taipei Mayor Ko, Chair of the Taiwan People’s Party and possible 2024 presidential candidate was pressed on the incursions by a city councillor objecting to the city holding the Taipei-Shanghai Twin-City Forum under the circumstances. Ko said in response that if he were president “my planes would also cross the median line, you can rest assured at that!”

Hopefully, this was one of Ko’s many off-the-cuff gaffes, not a carefully thought out position. While unlikely, it is possible he could be the next president if the next election is a complicated three- or four-way race.

In the June My-Formosa poll, respondents picked him as the third most suitable person to be the next president, only a narrow 1.9% behind the KMT’s Hou Yu-ih (侯友宜) — though 15.1% behind William Lai (賴清德) of the DPP. If a major scandal were to engulf the DPP, like it did in the waning years of the Chen Shui-bian (陳水扁) administration, Ko could stand a chance.

Ko needs to start thinking like a president, and ask himself what would sending the Air Force across the Davis Line accomplish? What message would it send to China, and nations friendly to Taiwan like the U.S. and Japan?

In the face of these Chinese incursions, Taiwan needs to prepare, not provoke.

Courtney Donovan Smith (石東文) is a regular contributing columnist for Taiwan News, the central Taiwan correspondent for ICRT FM100 Radio News, co-publisher of Compass Magazine, co-founder of Taiwan Report ( and former chair of the Taichung American Chamber of Commerce. Twitter: @donovan_smith.