More than a hundred leading intellectuals have signed an open letter calling for China’s national legislature to ratify a major human rights treaty as lawmakers are preparing to convene in Beijing next week to attend the inaugural session of the 12th National People’s Congress.

The letter comes at a crucial moment in China’s leadership transition as Xi Jinping, already General Secretary of the ruling Communist Party, is poised to succeed Hu Jintao as head of state in a carefully orchestrated transition pending approval of the rubber-stamp parliament next week.

The 121 signatories include renowned renowned scholars such as Hu Yong, Cui Weiping, He Weifang, Zhan Jiang, the economist Mao Yushi, lawyers Pu Zhiqiang and Xu Zhiyong, journalist Wang Keqin, environmental activist Dai Qing. Their letter is reminiscent of the Charter ’08, a similar open letter five years ago which landed Nobel Peace Laureate in jail for subversion, but is much less outspoken in its demands.

China had signed the International Covenant on Civil and Political Rights on occasion of the 50th anniversary of the Universal Declaration of Human Rights in 1998, but the National People’s Congress has so far failed to ratify it. In 2004, President Hu Jintao and Premier Wen Jiabao have publicly expressed support for the treaty’s ratification. In 2005, then Politburo Standing Committee member Luo Gan also said that the treaty should be ratified in China “as soon as conditions allow.”

The international treaty obligates countries, which have chosen to sign and ratify it, to respect freedom of speech, assembly, religion, the right for a fair trial and others.

Most of the rights listed in the treaty are already guaranteed in the Chinese constitution. Those rights cannot be  enforced in China’s courts. Xi Jinping has raised eyebrows and hopes in December when he publicly promised that the enforcement of constitution would “reach a new level.”

The open letter was meant to be released in a prominent Chinese newspaper on Thursday, according to the China Media Project at the University of Hong Kong, but censors found out about it and thus had to be leaked in advance.

The CMP has a translation of the full text of the letter.