But it also threatens to backfire as Taiwan's presidential election draws closer, with United States and Australian concerns about China's growing footprint in the Pacific strengthening Ms Tsai's argument that Beijing poses a threat to Taiwan and regional order.
"Their diplomatic offensives and military coercion pose a serious challenge to regional stability and peace".
China says the two sides must be eventually reunited, by force if needed.
Tsai said China "is encroaching on us through sharp power", and asserted that Taiwan would work with like-minded nations to ensure that the "peaceful and stable cross-strait status quo is not unilaterally altered".
The DPP favours and advocates for a separate Taiwanese identity, while the pro-China KMT traditionally sees Taiwan as the Republic of China.
It was at that same square in 1949 that Mao Zedong proclaimed victory after the communist defeat of the nationalists in a civil war which forced Chiang Kai-shek and his Republic of China government under the Kuomintang (KMT) party to retreat to Taiwan.
Resistance to China was a major theme in the speech.
Taiwan's President Tsai Ing-wen on Thursday rejected a "one country, two systems" formula that Beijing has suggested could be used to unify the island and the mainland, saying such an arrangement had set Hong Kong "on the verge of chaos". Tsai has considered offering asylum to protesters on humanitarian grounds. Her chief election opponent espouses friendlier relations with China.
"When freedom and democracy are challenged, and when the Republic of China's existence and development are threatened, we must stand up and defend ourselves", Tsai said, referring to Taiwan by its official name.
Cruz arrived in Taiwan Thursday morning on a two-day visit to attend the National Day activities, becoming the first sitting US senator in 35 years to participate in the celebrations, according to Tsai.
Ross Darrell Feingold, a Taipei-based lawyer and political risk consultant who has over 20 years' experience advising clients on transactions in Taiwan, told Nikkei the upcoming elections is Tsai's to lose. "As the strategic forefront of the Indo-Pacific region, Taiwan has become the first line of defense for democratic values".
Rigger said the annual speech was an opportunity to affirm shared strengths and values.
Chen and others said that the government must take advantage of a favorable global climate toward Taiwan to discard the ROC and replace it with Taiwan.
Because of ongoing trade frictions with Washington, Beijing probably won't rebut Tsai's speech, Huang said.
The Taiwanese people walked the hard path to democratisation together, and though it may sometimes be tumultuous, only democracy can ensure our hard-won freedom and offer the next generation the right to choose their own future.
The protests were headed by the 908 Taiwan Republic Campaign and the Taiwan Action Alliance Party (TAPA), with supporters gathering in front of the Presidential Office Building.