A series of exchanges between President Chen Shui-bian (
Some observers and politicians, however, believe visible friction between Hsieh and Chen is part of the DPP campaign strategy to team up contrasting strengths.
A high-ranking government official and former DPP strategy adviser said Chen and Hsieh's "disagreements" indicate "close cooperation, with an appropriate division of labor."
"It is like what Hsieh said: It would be pointless to elect a president that is not much different from the previous one," said the official, who spoke on condition of anonymity.
The official said that national identity and sovereignty were decisive issues in the election and key to the DPP's campaign strategy because they have long been the party's core platform.
A candidate's capacity to improve the economy, on the other hand, only becomes clear with performance, he said.
Hsieh's position on identity issues is clear to the public, he said, which is why the DPP hopeful is focusing his platform on the economy at this stage.
Chen, by comparison, sees elections from a different perspective and believes the sovereignty issue is not only key in elections, but also a matter of life and death for Taiwan, the official said.
"If Hsieh is practicing political Tai Chi -- emphasizing love, trust, reconciliation and coexistence -- Chen is a warrior fighting bloody battles on the frontline," he said. "It does not necessarily mean there is a divergence of values or the direction the party will take. They just have different styles."
While Chen and former DPP chairman Yu Shyi-kun work on consolidating the pan-green camp's support base, Hsieh believes he should first woo "centrist" voters by addressing economic issues, the official said, adding that "deep green" voters could be counted on.
The official dismissed criticism that Chen's vocal campaign against the Chinese Nationalist Party (KMT) and its presidential candidate, Ma Ying-jeou (馬英九), is overshadowing Hsieh and forcing him to play second fiddle at a time when he should be showing off leadership skills.
That is not a concern, the official said, because Hsieh has taken charge of his campaign and feels comfortable taking the lead.
"It is true that the roles of leading and supporting actors must be clearly separated, but sometimes the supporting actor plays an important part," the official said. "I think Hsieh most likely thought things through in advance and realized he needed to share the work load with Chen."
Jerome Keating, a political analyst based in Taipei, said he believes the increasingly apparent contrast between Chen and Hsieh is not so much a campaign strategy as the result of two different campaign styles.
"I do think they need to talk to each other," Keating said.
Chen and Hsieh "possibly could work out a strategy, but I don't see the strategy yet," he said, adding that Chen and Hsieh could use a "good cop, bad cop" arrangement to make tough comments without hurting Hsieh at the polls.
Keating said he hoped Hsieh realized the identity issue was not the only key issue in this election, adding that neglecting to address other concerns could backfire.