Over the past week, Chen has suggested amending the constitution to emphasize Taiwan's distinction from its giant neighbor, including renouncing the self-governing island's claim to all of China.

Beijing predictably assailed Chen's recent comments.

"Whoever attempts to separate Taiwan from China by any means is playing with fire and is bound to go up in flames, suffering an ignominious defeat," said Li Weiyi, a spokesman for China's Cabinet-level Taiwan Affairs Office.

On Thursday, at the 20th anniversary celebration of his Democratic Progressive Party, Chen again differentiated between the two sides.

"Taiwan is Taiwan, China is China," he said. "They are two completely different countries."

Analysts in Taipei see Chen's approach as an effort to rally domestic support in the face of months of attacks over allegations of corruption surrounding his family and inner circle.

Lin Chong-pin (林中斌) of suburban Taipei's Tamkang University said Chen's comments on a new territorial definition were meant to appeal to his core supporters.

"Each time he finds himself in a corner, he will choose to rally his fundamentalist (independence) supporters," he said.

However, he said, Chen will be careful to present a more moderate face to the outside world to avoid giving the impression he is trying to stoke confrontation with Beijing.

"(He) sounds like he's close to a declaration of independence when he addresses the rank-and-file, but when he talks to outsiders, he will emphasize government efficiency," Lin said.

Political scientist Lo Chih-cheng (羅致政) from private research group Taiwan Thinktank agreed. He said that in order to minimize international fallout, the ruling party will argue that changes to the constitution will solidify the island's democratic system, rather than create new territorial facts.

But regardless of how Chen proceeds, he has to be sensitive to the concerns of the United States, Taiwan's most important foreign ally.

Despite hinting that it would assist Taiwan if China attacks, Washington fears being drawn into conflict in the western Pacific, and works hard to prevent it from breaking out.

On Monday, a U.S. State Department spokesman criticized Chen's proposed territorial alterations, saying Washington does not support Taiwan independence and opposes unilateral changes to the status quo by either side.

Liu Pi-jung (劉必榮) from Taipei's Soochow University said Chen would be hard-pressed not to get the message.

"U.S. pressure will be effective," Liu said.

Shih Cheng-feng (施正鋒) of the Taipei-based Institute for National Development cautioned that any move by Chen to amend the constitution would almost certainly fail because, with only a minority of legislative seats under his control, he cannot hope to muster the three-quarters legislative majority constitutional change requires.

Still, Shih said, Chen might decide to try.

"Chen cannot realize his promises, but at least he can tell his supporters that he made the effort," Shih said.