Critics accused him of betraying the party he headed, secret support of Taiwanese independence, and involvement in corruption (black gold politics).
After leaving office Lee was expelled from the KMT for his role in founding the pro-independence Taiwan Solidarity Union (TSU), which forms part of the Pan-Green Coalition alongside Taiwan's Democratic Progressive Party. Lee is considered the "spiritual leader" of the TSU, and has recruited for the party in the past. Lee has been outspoken in support for Taiwanese independence though not necessarily a formal declaration. In 2013, a first trial cleared him for his hypothetical involvement in a corruption scandal..