These minor political and environmental victories are significant for the opposition. The DPP has long portrayed itself as the greener of Taiwan's two major political parties. It has long advocated dismantling Taiwan's nuclear energy plants, and under Chen Shui-bian of the DPP, Taiwan's president from 2000 to 2008, the party attempted to halt the construction of Taiwan's fourth nuclear power station, which is located fairly near to the capital, Taipei. Mr Chen was ultimately forced to allow work on the plant to resume, under pressure from the KMT, but Ms Tsai has revived the issue in the wake of the nuclear crisis in Japan, which has had problems containing radiation leaks that have occurred since an earthquake and tsunami damaged several reactors in March. She has vowed to halt construction on the fourth nuclear facility and to phase out the use of the other plants by 2025. The KMT government has tried to reassure the public over safety concerns, but anti-nuclear protesters have taken to the streets in recent weeks. Many observers have long questioned the wisdom of situating nuclear facilities in Taiwan, which, like Japan, is subject to frequent earthquakes.

Environmental and safety issues resonate in Taiwan, especially when they are contrasted with the perceived narrow interests of industry and the wealthy. Ms Tsai will be able to capitalise on these issues to galvanise the DPP's support base over environmental and labour issues, as well as to harness public discontent over the growing disparity on the island between rich and poor. Yet she faces a significant obstacle with regard to her position on cross-Strait relations. It is a central tenet of the DPP's ideology that Taiwan is an independent country and that it should seek recognition from the international community of its de facto sovereignty. As a result of its aspirations for Taiwan to remain permanently independent of China, the DPP has generally resisted a deepening of economic exchanges with the mainland, fearing that this could eventually undermine Taiwan's self-governance. If she is elected, Ms Tsai has promised to review the Economic Co-operation Framework Agreement (ECFA, a loose bilateral free-trade deal) that Mr Ma has negotiated with China. Although she is unlikely to undo the agreement, reopening the issue could increase cross-Strait tensions and adversely affect the economy. As if on cue, China released a statement just after Ms Tsai's nomination victory, warning that any move toward a permanent separation from China would damage the relationship between Taiwan and the mainland and "affect stability in the Taiwan Strait."

Ms Tsai's considerable intellectual gifts, her talent for voicing public concerns over environmental and labour issues and her ability to articulate widely held suspicions of China make her a formidable presidential candidate. Yet in order to defeat Mr Ma she will need to reassure voters that her cross-Strait platform will not result in an increase in bilateral tensions or the undoing of the generally popular liberalisation of Taiwan's trade relationship with China. If she fails to do this, the early opinion polls will come to look rather optimistic in hindsight.