TAIPEI, May 2 (AP) -- For years, Taiwan's main opposition party has downplayed its official line of unification with rival China, fearing that conciliatory gestures would be seen by the government as selling out the island's interests to the communist mainland.

But last week's "journey of peace" by Nationalist Party chief Lien Chan went a long way toward breaking the mold, drawing large-scale popular support at home, and undermining the ability of Taiwan President Chen Shui-bian to press ahead with his independence-leaning policies.

China considers Taiwan part of its territory and has been pressing for reunification since the two sides split amid civil war in 1949. It considers Chen a major obstacle in achieving that goal, and has been working to isolate him, prompting charges it exploited the Lien visit as part of a divide-and-rule policy toward Taiwan.

The trip to China constituted a big risk for Lien, whose party was ousted from power in presidential elections of 2000 and has since swiped at Chen from the relative obscurity of the legislature, where it controls about one-third of the seats.

Lien's position was further complicated earlier this year when China's National People's Congress passed an anti-secession law, codifying the mainland's right to use force if Taiwan moves toward permanent independence.

The measure created a firestorm of opposition in Taiwan, and appeared to boost Chen's position as an advocate of a separate identity for Taiwan, free from China.

But last week's televised images of Lien being lionized by cheering crowds in Beijing, Nanjing and Xi'an appear to have reversed the trend -- at least temporarily.

Public opinion polls conducted after his meeting Friday with Chinese President Hu Jintao reported a wide majority of Taiwanese holding positive views of the trip.

Political scientist Chiang Min-chin of Taipei University said mainland leaders won considerable goodwill by offering to end decades of enmity and granting trade benefits without forcefully pressing for unification.

"Taiwanese see for themselves that we can talk with China without compromising our interests," he said.

Lien was the first leader of a Taiwanese political party to set foot in mainland China. His high-profile visit -- stirring up what Taiwanese television stations described as a "Brother Lien fever" on the mainland -- had worried his colleagues, who feared their leader could be branded a communist sympathizer.

Plagued by a wooden style, the 68-year-old Xi'an native had been perceived as an uncharismatic apparatchik, with few prospects of shuffling Taiwan's political deck.

But that impression changed as Lien delighted an enthusiastic crowd at Peking University with rare touches of humor and won plaudits in the Taiwanese press for his deft performance with Chinese leaders.

Lien's newfound popularity -- providing it holds -- could seriously undercut Chen's prospects for moving forward with his independence-leaning agenda. Many leaders of Taiwan's powerful business community are already leery that pro-independence policies could provoke an armed reaction by China, and plunging support would significantly narrow Chen's political options.

Still, Lien's triumph could be short-lived. Political opinion in Taiwan is fickle and Chen has shown himself skillful at beating back the political initiatives of his opponents.

"Chen ... is not a person who will admit defeat," said Wu Chih-chung, of Taipei's Soochow University. "He stood up before when people were about to count him out."

During Lien's trip, Chen has made several appeals to Chinese leaders to begin talks with him.

He made a new call Monday, saying "the door for dialogue and negotiation is still open between the two sides. Under the principles of democracy, peace and parity, the two sides can at any time begin to have contact, dialogue and negotiations."