Considering Japan’s pacifist Constitution, I am not sure legally how they would be allowed to respond if just Taiwan was attacked. Additionally the Chinese would more likely blockade Taiwan prior to any attack which makes Japanese involvement even more Constitutionally difficult:
Tokyo would step up militarily to defend Taiwan if Beijing moved to reunify the island with mainland China by force, former deputy national security adviser Matt Pottinger said in a panel discussion on Tuesday with other top Trump administration officials.
Pottinger, considered one of the key architects of the Trump administration’s hardline China policies, said Japan first suggested a quadrilateral alliance with the US, India and Australia – now known as the “Quad” – as a defense strategy against China. He also pushed back on assertions that the former administration strained ties with Japan and other allies in the region. (…….)
“There’s a saying in the Japanese military: ‘Taiwan’s defense is Japan’s defense.’ And, and I think that Japan will act accordingly,” Pottinger added.
The Moon administration is already trying to backtrack on the Joint statement made by President Moon and President Biden during last week’s summit:
The government has stepped up efforts to prevent any fallout from President Moon Jae-in’s summit with U.S. President Joe Biden adversely affecting South Korea’s ties with China, with the foreign minister saying their post-summit statement touching on Taiwan was “theoretical and principled.”
President Moon and his U.S. counterpart held their first in-person meeting at the White House last week and their joint statement referred to the importance of preserving peace and stability in the Taiwan Strait. It also referred to freedom of navigation and overflights in the South China Sea and beyond.
Despite not directly mentioning China, it was seen as a sign that South Korea agreed with the U.S.’s anti-China campaign, and this drew a strong response from Beijing.
Here is an interesting issue that I doubt the Moon administration would do anything to change:
Growing anti-China sentiment is leading some to call for taking away the right of foreign permanent residents to vote here.
The move is intended to target Chinese residents, as they make up the majority of eligible immigrant voters in Korea. Recent disputes have pitted the people of the two countries against each other over various cultural issues, including recent claims coming from China that some elements of Korean culture, including kimchi, hanbok and samgyetang, originated there.
The anti-China sentiment has always been there in the Korean public; it is just incidents like this bring it out publicly:
The Chinatown issue comes on the back of Koreans’ protesting claims made by some Chinese influencers and media that kimchi is their traditional food. After Beijing received an international certification for its pickled vegetable dish, “paocai,” in November, China’s state-run Global Times reported that this certification amounted to “an international standard for the kimchi industry led by China.” Since then, the nationalist newspaper has been running articles containing the implication that Beijing is leading the kimchi industry and that the dish originated in China.
These articles led to an online spat between the internet users of both countries, with Koreans arguing that China was now attempting to steal Korea’s cultural legacy.
As long as the Korean left remains in power I just don’t see them joining the “Quad” because of their near religious zeal of improving relations with North Korea. Additionally even if the Korean right was to regain power even they would be challenged to join the quad considering the heavy economic investment that Korean companies have made in China that would be impacted:
Korea may face tougher pressure from China to avoid joining the U.S.-led informal strategic group, as Beijing reportedly remains on high alert over Seoul’s possible participation.
Citing diplomatic sources, the Hong Kong-based South China Morning Post (SCMP) reported Saturday that Korea had received a number of inquiries from Chinese officials about whether it was considering joining the Quadrilateral Security Dialogue or “Quad.” But the Korean government has so far said that there has been no invitation from Washington.
The report also said that Chinese diplomatic experts believe that if Korea were to join the Quad, it would be a significant challenge to China’s security in East Asia, while referring to the alliance as an “anti-China coalition” in the region.
Here is another example of the Chinese using their auxiliaries to push around a weaker neighbor in the South China Sea. The Philippines is in a tough spot because if they send in Coast Guard and Naval assets to remove the auxiliaries than that gives the Chinese military the excuse to move in and protect them. This is a fight the Philippines cannot win thus why they are turning to the international media:
The Philippine defense chief on Sunday demanded more than 200 Chinese vessels he said were manned by militias leave a South China Sea reef claimed by Manila, saying their presence was a “provocative action of militarizing the area.”
“We call on the Chinese to stop this incursion and immediately recall these boats violating our maritime rights and encroaching into our sovereign territory,” Lorenzana said in a statement, adding without elaborating that the Philippines would uphold its sovereign rights.
A government watchdog overseeing the disputed region said about 220 Chinese vessels were seen moored at Whitsun Reef, which Beijing also claims, on March 7. It released pictures of the vessels side by side in one of the most hotly contested areas of the strategic waterway.
Increasingly more foreigners are choosing to not travel to China for fear of being detained:
The dramatic detention of a handful of foreigners in recent years has instilled a deep fear in some people, especially those with politically adjacent occupations. As President Xi breeds a culture of nationalism and forges increasingly hostile relations with Western governments, some fear that if a diplomatic spat between their government and Beijing occurred while they were in China they could become a target.