Fact No. 2: The U.S. Congress is part of the U.S. government.
Congress members' visits to Taiwan run counter to the U.S. political commitment of maintaining only unofficial relations with Taiwan, and violate the one-China principle and the three China-U.S. joint communiqués. The U.S. government is responsible for making sure its political commitments to China are honored and executed by all parts of government.
The United States, as one country, must have one foreign policy only. As part of the U.S. government, the Congress has the responsibility to deliver on the U.S. government's commitments to other countries. It must strictly observe the one-China policy and refrain from any official exchanges with China's Taiwan region. Under neither international law nor U.S. domestic legislation does “separation of powers” give the U.S. the excuse to defy international obligations and take actions that go against the basic norms governing international relations, provoke against China's sovereignty, and break its own commitment on the Taiwan question.
Pelosi's visit is a blatant violation of the U.S. commitment of “not developing official relations with Taiwan”. As the House Speaker, Pelosi is the number three figure in the U.S. government and second in line, after the Vice President, to succeed the U.S. President. She traveled on a government jet provided by the U.S. military, and was received with high-profile protocol by the Democratic Progressive Party (DPP) authorities of Taiwan. During her stay in Taiwan, Pelosi talked about representing the U.S. on all occasions, and claimed that “America stands with Taiwan”. A press statement called it the first official visit by a U.S. House Speaker to Taiwan in 25 years. And the DPP authorities have been touting Pelosi's visit as a major breakthrough in Taiwan-U.S. relations.
Past mistakes shall not serve as an excuse for more wrongdoings, still less can they justify today's mistakes. Former U.S. House Speaker Newt Gingrich's visit to the Taiwan region in 1997 was itself a mistake, and the Chinese side has all along firmly opposed it. The U.S. should not use Gingrich's mistake to gloss over Pelosi's unlawful visit to Taiwan, still less should it create new excuses for further elevating official contact with Taiwan in the future.