In 1985, as the editor of the weekly pro-democracy magazine Neo-Formosa, he was jailed for libel following publication of an article critical of Elmer Fung, a college philosophy professor who was later elected a New Party legislator.

After being released, Chen helped found the Democratic Progressive Party (DPP) in 1986 and was elected a member of the Legislative Yuan in 1989, and Mayor of Taipei in 1994.

While his client Huang Hsin-chieh, the leading opposition dissident, and seven co-defendants, including his future Vice President Annette Lu, were found guilty, Chen came to be known for his forceful and colorful arguments.

On 12 January 1985, Chen was sentenced to a year in prison for libel as a result of his editorship of Neo-Formosa, following the publication of an article which claimed that the doctoral dissertation of Elmer Fung, a college philosophy professor (who would later become a New Party legislator), was plagiarized.

[16][17] Chen lost his appeal in May 1986 and began serving eight months in the Tucheng Penitentiary along with Huang Tien-fu and Lee I-yang, two other defendants in the case.

[citation needed] Chen was elected as the mayor of Taipei in 1994, largely as the result of a vote split between the KMT incumbent Huang Ta-chou and the KMT-spin-off New Party (NP) candidate Jaw Shaw-kong.

Unable to find experienced bureaucrats from his own party, Chen and his inner circle of young law school graduates retained many of the KMT administrators and delegated considerable authority.

Chen also made highly publicized evictions of longtime KMT squatters on municipal land, and ordered Chiang Wei-kuo's estate demolished.

In his first autobiography, "The Son of Taiwan", Chen wrote that he was not entirely upset about losing the re-election as it gave him opportunity to find out what areas in his political career he could improve.

For example, he wrote that mainland Chinese people generally approved of his social and economic improvements in Taipei, but they ultimately voted for Ma because of ethnic tensions.

One concession that the legislature made was to include a provision for an emergency defensive referendum and during the legislative debates it was widely believed that this clause would only be invoked if Taiwan was under imminent threat of attack from China as has been so often threatened.

Within a day of the passage of the referendum bill, Chen stated his intention to invoke this provision, citing PRC's over 450 missiles aimed directly at the Taiwanese.

Pan-Blue believed that his bill was only intended to benefit Chen in the coming election, as whether PRC removes the missiles would not be pressured or decided by referendum result.

This high-profile trip raised Chen's standing in opinion polls ahead of his opponent Lien Chan for the first time at 35%, according to Agence France-Presse.

The PRC has stated many times that it cares little about what Chen says, but will watch closely in the next few months to see what he does, a standard sentence that Communist China continues to quote.

In late 2004, in effort to maintain the balance of power in the region, Chen began eagerly pushing for a US$18 billion arms purchase from the United States, but the Pan-Blue Coalition repeatedly blocked the deal in the legislature.

On 14 December 2004, following the failure of the Pan-Green coalition to gain a majority of seats in the 2004 ROC legislative election (as many had expected to occur), Chen resigned as chairman of the DPP.

Under agreement with the Vatican, Italy permitted all guests to the funeral passage without hindrance and Chen was received at the airport in his capacity as a foreign head of state.

He met with members of the U.S. Congress through video conference and was invited to visit Washington, D.C. On his way back, he was originally scheduled to fly through San Francisco.

[31] Support from his own party had also dropped with a few prominent members, such as Shih Ming-teh, calling for his resignation in the Million Voices Against Corruption, President Chen Must Go campaign.

[31] In related charges, there were accusations from the opposition party that Chen Shui-bian's wife was involved in trading stocks and obtaining Pacific Sogo Department Store's gift certificates illegally in exchange for settling the disputed ownership.

[citation needed] On 1 June 2006, Chen declared that he was handing control of governmental matters to Premier of the Republic of China, Su Tseng-chang, and announced he would not be involved in campaigning.

During questioning at the presidential Office on the afternoon of 7 August 2006, the president detailed to the prosecutor how he spent the fund and presented relevant receipts and bank remittance statements.

Soong sued the president after Chen repeatedly accused him of secretly meeting the director of the People's Republic of China's Taiwan Affairs Office.

[35] On 3 November 2006, Chen's wife Wu Shu-chen and three other high-ranking officials of the Presidential Office were indicted of corruption of NT$14.8 million (US$450,000) of government funds using faked documents.

[37] In mid-June 2007, opposition pan-blue camp lawmakers initiated a recall motion that would allow the voters to remove Chen from power via a public referendum.

On 20 June, Chen addressed the nation by television, denying any involvement of the first family or himself (other than his son-in-law) in any of the alleged scandals, or "directly" accepting the department's gift certificates.

The documents consisted mainly of receipts and other records of special expenses, which according to Ma's chief aide assured pose no danger to the country's interests once declassified.

[43] After two years of investigation, it was found that Chen Shui-bian received millions from the owners of the TCC Company after the government bought the Longtan land, which was then integrated into the Science Park project.

However, in August 2002, frustrated by a lack of reciprocation from the PRC, he described the relationship as "one country on each side" and initiated a referendum on cross-strait relations in 2004, returning to a more confrontational stance.