With attorneys locked up, harassed or plain scared, two prominent dissidents will defend themselves against charges of subversion Thursday in China's highest-profile dissident trials in two years. Releasing Liu Nianchun appeared to be an attempt by the government to blunt international criticism over Monday's upcoming trial of prominent dissident Xu Wenli. Xu is the third leading member of a would-be opposition political party put on trial for subversion in a three-week crackdown that has seen 30 dissidents arrested or interrogated. The dissident, Yao Zhenxian is a leader of the China Democracy Party, which was formed in June during President Clinton's visit to China.