No one dared to speak up, but Lai said, "The best possible outcome is that Your Imperial Majesty can remain a kind father and that the Crown Prince can live out his years."
In 651, Lai Ji was made Zhongshu Shilang (中書侍郎), the deputy head of the legislative bureau, and he became an official in charge of editing the imperial history.
In 655, he was made Zhongshu Ling (中書令), the head of the legislative bureau and a post considered one for a chancellor, as well as the acting minister of civil service.
However, in 655, he, over the explicit opposition of Lai, Han, and the highly regarded chancellor Chu Suiliang, as well as the implicit disapproval by his own powerful uncle Zhangsun Wuji, deposed Empress Wang and replaced her with Consort Wu.
After Empress Wu's ascension, she submitted a petition ostensibly praising the faithfulness of Han and Lai in opposing the unprecedented Chenfei title, but showing instead that she remembered that they had offended her.
In 656, after Empress Wu's son Li Hong was created crown prince (displacing Emperor Gaozong's oldest son Li Zhong, whose mother Consort Liu was of low birth), Lai was made a junior advisor to the young crown prince, and his title was upgraded to that of a marquess.
In 657, however, with Empress Wu and her allies Xu Jingzong and Li Yifu beginning to carry out a series of reprisals against officials who had opposed Empress Wu's ascension, Xu and Li falsely accused Han and Lai of encouraging Chu (who by that point had been demoted to the post of commandant at Gui Prefecture (桂州, roughly modern Guilin, Guangxi)) to rebel.