More than 100,000 Taiwanese took to the streets Saturday to demand the island's return to the United Nations, giving ballast to President Chen Shui-bian's pro-independence policies, and defying threats from rival China.

The demonstration in the southern port city of Kaohsiung was the most important step yet in an 18 month government-orchestrated campaign to emphasize Taiwan's separateness from the mainland, from which it split amid civil war in 1949.

Sporting a green and white T-shirt emblazoned with the slogan "UN for Taiwan," Chen was the obvious star of the rally, which was called to back a planned referendum on membership in the world body under the name Taiwan, rather than the official title of the Republic of China.

He far outshone Frank Hsieh, the candidate of his ruling Democratic Progressive Party in next March's presidential elections.

Surrounded by cheering supporters, Chen led marchers through the Kaohsiung streets amid colorful banners and rippling flags, looking poised and confident.

It was a remarkable comeback for a man who only a year ago was written off as an embarrassment by the DPP, which feared that a series of corruption sandals involving his family and inner circle would doom it to defeat in the upcoming presidential poll.

But now it is the main opposition Nationalist Party that seem to be caught off balance, torn between its support for eventual unification with the mainland, and its recognition that U.N. membership is a huge vote getter with the Taiwanese public.

Reflecting the party's dilemma, Nationalist presidential candidate Ma Ying-jeou held his own pro-U.N. membership rally on Saturday, attracting about 50,000 supporters to the central city of Taichung.

But unlike the DPP rally 200 kilometers (126 miles) to the south, this one pushed for Taiwan's U.N. re-entry under its official Republic of China name.

The distinction is a crucial one.

The Republic of China title indicates fealty to the "one China" concept, which has been at the heart of the communist mainland's Taiwan policy since their split almost 60 years ago.

By contrast, use of the Taiwan name signals a strong bent toward independence — strongly favored by Chen, but so intensely opposed by China that is has vowed to attack if it ever becomes reality.

Beijing has blasted the DPP U.N. campaign in unusually strong language, accusing Chen of separatism, and saying he will be called before the bar of history to answer for his actions.

China regards Taiwan as part of its territory and insists it has no right to the sovereign status accorded to normal states.

The U.S. has also criticized the DPP U.N. effort, saying it could provoke a new bout of instability in the perennially volatile Taiwan Strait, which separates the self-governing island from the mainland.

The U.N. campaign is only the latest in a series of initiatives Chen has sponsored to emphasize Taiwan's separateness from China.

Since scraping a government body responsible for unification with the mainland in late February 2006, he has systematically attacked the legacy of late dictator and unification icon Chiang Kai-shek and stricken the China name from a number of government companies — replacing it with that of Taiwan.

He has also pushed for a far reaching edit of school textbooks to de-emphasize Taiwan's historical and cultural links to the mainland.

The moves have helped crystallize a strong sense of Taiwanese identity among DPP supporters, many of whom are descendants of people who came to the island from the Chinese mainland in the 17th and 18th centuries.

By contrast the Nationalist core constituency consists of the families of mainland Chinese who arrived on the island in 1949 after the Nationalists were defeated by Mao Zedong's Communists.

For all the sound and fury of Saturday's U.N. rallies, they are largely symbolic actions.

Taiwanese U.N. membership would still need approval by the Security Council, and with China opposed to the island's entry under any name at all, it would almost certainly wield its veto to stop it.