In 2001, Chen returned to the Legislative Yuan as a representative of Tainan County. He became the Republic of China's thirty-second Foreign Minister in 2004. After Frank Hsieh resigned his Premiership and a subsequent cabinet shuffle, Chen became the Secretary of the Presidential Office. In 2004, Chen gained international attention and prompted substantial criticism worldwide after he commented that Singapore is a "booger-size country" that "holding China's ball sacks" with both hands, known as the "LP incident". Subsequently, the Singaporean Foreign Ministry has issued a statement warning Taiwan authorities to "not belittle Singapore, and avoid using “vulgar words to hurt others". Despite such comment, Singaporean politicians and lawmakers across the board and political spectrum overall refused to be drawn into a war of words or tensions over Chen's comments, which were described as "vulgar" and "undiplomatic", and even prompted criticism from some Taiwanese politicians, who urged him to withdraw such comments to avoid letting Singapore-Taiwan relations from deteriorating over the incident. However, Chen has not since taken back such words, but overall bilateral relations were not otherwise affected.