By John Ruwitch and Michael Martina


The closing session of the five-yearly party congress also changed the party constitution to explicitly endorse reform and opening as "the path to a stronger China" and made a nod towards growing environmental problems by promoting "ecological progress" as part of the party's development strategy.

"The party should attach greater importance to conducting oversight of cadres," the amendment said.

This would help improve "public trust in the selection and appointment of party cadres" and encourage top officials to be better examples, said a statement from the congress.

Bo, once widely considered a contender for top office, was expelled from the party this year and faces possible charges of corruption and abuse of power. His wife was jailed for murdering a British businessman in a scandal that has shaken the country and raised unsettling questions about the party's leadership.

President Hu Jintao warned in his state-of-the-nation address to the congress last week that corruption threatened the party and the state.

Without an independent judiciary, efforts to fight graft, a key driver of social unrest in the world's second-largest economy, will almost certainly falter, and the control-obsessed party has shown no sign of embarking on this reform.

But the party said there would be no reversing down the road to economic opening up, a policy begun some three decades ago, kicking off China's on-going boom.

"It is reform and opening up that will ensure China's future development," it said.

The party charter is less a legal document than a compilation of the ideological justifications the Communists have accumulated - and often quietly shelved - in their 91-year evolution from a rag-tag troupe of idealistic revolutionaries to cautious leaders of the world's most populous nation.

Party congresses are highly choreographed events that anoint new leaders, set the direction of the country's policy compass, and are an occasion for outgoing politicians to cement their legacies and perhaps designate their successors.

The charter also added outgoing party chief Hu Jintao's theory promoting equitable and sustainable development alongside Marxism-Leninism, "Mao Zedong Thought", "Deng Xiaoping Theory" and Hu's immediate predecessor Jiang Zemin's "Three Represents" theory as a guiding ideology, cementing Hu's legacy.

In 2002, Jiang's "Three Represents" was written into the party charter, stamping his imprint by opening the door to private entrepreneurs entering the party.

Hu is expected to be replaced as general secretary of the party by Xi Jinping, the current vice president, on Thursday.

(Additional reporting by Sui-Lee Wee, Michael Martina and Ben Blanchard; Editing by Nick Macfie)