Politically, Chen must now work with the party he throttled, the Nationalists, who still hold a 555 percent majority in the legislature and could frustrate his attempts at reform. His critics, and even some admirers, worry that Chen is not experienced enough to handle the delicate triangular relationship among Taiwan, China and the United States.
Regarded as an effective mayor of Taipei, he is seen by many as a leader better suited to domestic policy issues. Unlike his presidential opponents, who hold degrees from U.S. schools such as Georgetown and the University of Chicago, Chen was educated entirely in Taiwan and is uncomfortable speaking English.
On the streets of Taipei last night, though, none of that seemed to matter to Chen's supporters, who rode around on motorbikes, firing off air horns and flying green-and-white flags, the colors of the DPP. They had much to celebrate.
Two decades ago, Taiwan was a police state. When dissidents tried to march through the southern city of Kaohsiung in 1979, they clashed with police who tried to stop them. Some received life sentences for sedition.
After the regime's lifting of nearly four decades of martial law in 1987 and the legalization of political parties in 1989, the DPP began its formal climb to the political pinnacle it reached last night.
Many saw yesterday's victory as a lesson and a warning to the aging authoritarian leaders in Beijing. The threats they use to repress their own people don't play well on this democratic island of 22 million.
During Taiwan's first direct presidential election four years ago, China fired missiles off the coast in hopes of defeating incumbent President Lee.
The United States, which has pledged under somewhat vague terms to defend Taiwan, sent aircraft carriers to the area in a show of force.
Lee won in a landslide.
"I hope that in the future, they will never try this trick again," said Parris Chang, a Chen adviser and president of the Taiwan Institute for Political, Economic and Strategic Studies. "They try it every four years, and most times it doesn't work."