U.S. President Trump and Chinese President Xi Jinping [Xinhua/Yonhap News]

The Taiwan issue, a key sticking point between the U.S. and China, is re-emerging as a variable following U.S. President Donald Trump's request to postpone the summit, effectively delaying his visit to China.

Particular attention is being paid to whether the U.S. schedule for arms sales to Taiwan will be affected.

According to foreign media reports, including Reuters on the 18th, President Trump stated on the 16th (local time) that he requested the postponement of the summit with China due to the war with Iran. The Chinese Ministry of Foreign Affairs also effectively acknowledged the schedule postponement the previous day, stating that both countries are continuing to communicate regarding the timing of the visit.

This summit was initially expected to be an opportunity to coordinate sensitive issues between the two countries, including the Taiwan issue, which was not fully addressed at the Busan summit last year.

In particular, it was anticipated that the Taiwan issue would be a core agenda item, as President Xi Jinping had defined it as "the most important issue in Sino-U.S. relations" in a phone call with President Trump in February and demanded that "arms sales to Taiwan must be handled cautiously."

The U.S. had also adopted a cautious stance on arms sales to Taiwan ahead of the summit.

The New York Times reported last month that the Trump administration, while pursuing arms sales to Taiwan worth approximately $13 billion (about 19.3 trillion won), postponed the announcement due to concerns about China's backlash.

Reuters reported that the U.S. government was preparing to approve arms sales to Taiwan worth up to $14 billion (about 20.8 trillion won), including Patriot (PAC-3) and the National Advanced Surface-to-Air Missile System (NASAMS), following President Trump's visit to China.

Hong Kong's Ming Pao also reported that President Trump may approve a large-scale military package after his visit to China.

With the arms sales card still in play, there are also speculations that the arms sales schedule may also be delayed due to the postponement of the summit.

However, both Taiwan and the U.S. have collectively dismissed the possibility of delays in arms supply.

Gu Li-hsiung, Taiwan's Minister of National Defense, told reporters before attending the Legislative Yuan the previous day, "We are in close communication with the United States."

Stanley Brown, Deputy Assistant Secretary of State for Political-Military Affairs at the U.S. Department of State, also responded "no" when asked at a congressional hearing whether "arms transfers to Taiwan have been delayed."

He emphasized that there has been no change in the policy of supplying arms to Taiwan, despite the war with Iran.

However, Wen Il-hyun, a professor at China University of Political Science and Law, said in a radio interview on the same day that "President Trump's postponed visit to China may narrow the U.S.'s room for negotiation," and "in that process, there is a possibility of some concessions on the Taiwan issue."

Experts suggest that the postponement of this visit to China may be a signal of "speed adjustment" in U.S.-China negotiations, beyond a simple schedule adjustment, and may have unfavorable implications for Taiwan.

Guo Cheng, an international relations expert, analyzed at a seminar that "currently, the U.S.'s tariff policy is not only facing legal challenges domestically but also has the potential to increase inflationary pressures," adding that "in this situation, the negotiation cards that the U.S. can use against China are relatively limited."

He added, "This prolonged state of insufficient bargaining power is not desirable from Taiwan's perspective and could instead be disadvantageous."

Lin Jian, spokesperson for the Chinese Ministry of Foreign Affairs, responded to a question at a regular press briefing on the same day: "Is the timeline (changed by President Trump) one that China can agree to? Will China pursue more substantive discussions as both sides have more time to prepare for the meeting?" He stated, "Summit diplomacy has played an irreplaceable guiding role in Sino-U.S. relations. China and the U.S. will continue to maintain communication on the matter of President Trump's visit to China."