柯文哲因涉及京華城容積率案、政治獻金案以及挪用眾望基金會資金等案件，於 2026 年 3 月 26 日遭台北地方法院一審判處合併執行有期徒刑 17 年，並褫奪公權 6 年。BBC等媒體亦報導了該判決及其政治影響。

此判決對台灣民眾黨造成了嚴重衝擊，核心原因主要在於支持者信心的崩解。首先，「清廉形象」的破滅是最大打擊來源。柯文哲長期主打「新政治」與清廉政治路線，但隨著判決結果出爐，民眾黨支持度在 2026 年 3 月底跌至約 8.5% 的歷史低點，且超過六成民眾對該黨未來走向持悲觀看法，甚至認為可能泡沫化。同時，有超過半數受訪者不再相信柯文哲清白，顯示其核心政治品牌已嚴重受損。

其次，判決細節進一步加深震撼效應。法院判決指出涉及收賄（13年）、兩項公益侵占（2年、3年6月）與背信（2年6月），合併執行17年刑期。隨後公布長達391頁的判決書，內容包含多項證據細節，例如指示幕僚「橘子」出境、以及政治獻金被挪作私人用途等，使許多原本支持者出現強烈心理衝擊與信任崩潰。BBC

第三，此案幾乎切斷柯文哲的政治未來。由於一審重判17年並褫奪公權，外界普遍認為其參與 2028 年總統選舉的可能性已大幅降低，即使後續上訴成功翻盤難度也極高，使支持第三勢力的選民普遍感到失望與前景不明。

最後，支持者結構出現明顯分裂。一方面，仍有核心支持者持續聲援，並參與集會活動，堅持相信其清白；另一方面，中間選民與理性選民則持續流失。學者分析，過去一年民眾黨支持度已下降約 10 個百分點，顯示政黨基盤正在快速萎縮，而黨內接班與領導能力也遭到質疑。

整體而言，民眾黨正同時面臨「泡沫化危機」與「後柯時代接班困境」。雖然黨中央持續主張司法不公，但在具體判決證據公開後，要重新恢復社會信任與擴大中間選票，難度相當高。

Ko Wen-je was sentenced on March 26, 2026, by the Taipei District Court to a combined prison term of 17 years, along with deprivation of civil rights for 6 years. The conviction involved multiple cases, including the Jinghua City floor-area ratio controversy, illegal political donations, and misappropriation of funds from the Taiwan People’s Party-affiliated Foundation. BBC and other media reported on the ruling and its political impact.

The verdict has dealt a severe blow to the Taiwan People’s Party’s public support, primarily due to the collapse of voter confidence.

Firstly, the “clean governance” image that Ko long promoted has been severely damaged, with approval ratings dropping to historic lows. According to polling data at the end of March 2026, the party’s support fell to around 8.5%, with more than 60% of respondents expressing pessimism about its future and potential collapse. Belief in Ko’s innocence has also weakened significantly, with over half of the public no longer convinced that he is not guilty. This has severely undermined the “new politics” image that once attracted centrist voters. 

Secondly, the detailed court ruling intensified public shock. The judgment included multiple charges such as bribery (13 years), two counts of embezzlement of public interest funds (2 years and 3 years and 6 months), and breach of trust (2 years), resulting in the combined 17-year sentence. When the court later released a 391-page written judgment detailing evidence—such as instructions to an aide known as “Orange” to leave the country and the alleged use of political donations for personal expenses—many former supporters expressed emotional distress and disbelief. 

Thirdly, the ruling has effectively ended Ko’s political prospects for the 2028 presidential election. Analysts note that with a first-instance 17-year sentence and loss of civil rights, the likelihood of successfully appealing to overturn the conviction is extremely low, which has left supporters of a “third force” political alternative feeling disillusioned. 

Finally, the party’s supporter base has become deeply polarized. Hard-core supporters continue to defend Ko, with the party mobilizing rallies to show support and Ko himself insisting that he “will not surrender.” However, more moderate and centrist voters have continued to leave. Scholars estimate that the party has lost around 10 percentage points of support over the past year, and there is growing skepticism about whether current leadership figures such as Huang Kuo-chang can sustain the party’s momentum.

Overall, the Taiwan People’s Party is now facing both a potential “bubble burst” and a leadership transition crisis. While the party continues to claim political persecution, the detailed court evidence has made it increasingly difficult to restore public trust or expand its centrist voter base.