In a year of scandals and corruption charges at the commanding heights of the Communist Party, a retired party chief some had written off as a spent force has thrust himself back into China's most important political decisions and emerged as a dominant figure shaping the future leadership.
The resurgence of Jiang Zemin, the 86-year-old former leader, is all the more striking because he was said last year to be near death. But over recent months, Mr. Jiang, who left office a decade ago, has worked assiduously behind the scenes, voicing frustration with the record of his successor, Hu Jintao, and maneuvering to have his protégés dominate the party's incoming ruling group.
He even weighed in on how to deal with Bo Xilai, the populist political figure who was caught up in a major scandal and was investigated after his wife was accused of murdering a British businessman.
Mr. Jiang has also sought to shape policy, party insiders say, by proposing changes to an agenda-setting report presented Thursday at the start of the 18th Party Congress, the weeklong meeting that precedes the naming of Mr. Hu's replacement and a new generation of leaders. Mr. Jiang and Mr. Hu arrived together at the Great Hall of the People, before others in the senior leadership — another sign of Mr. Jiang's influence.
Mr. Jiang's goal, those insiders say, appears to be to put China back on a path toward market-oriented economic policies that he and his allies argue stagnated under a decade of cautious leadership by Mr. Hu, a colorless party leader who favored more traditional socialist programs and allowed gargantuan state-owned companies to amass greater wealth and influence.
Many see Mr. Jiang, who brought China into the World Trade Organization and rebuilt ties to the United States after a breakdown in 1989, as favoring deeper ties to the West and more opportunities for China's private sector.
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Mr. Jiang was able to outflank Mr. Hu to shape a new lineup for the Politburo Standing Committee, the top decision-making body, which appears to have Jiang allies chosen for five of the projected seven seats, according to party insiders. The most prominent is Xi Jinping, the designated heir to Mr. Hu as party chief and president.
"Look at the final seven people and you know who the big winner is: Jiang, or Jiang and Xi," said an editor at a party media organization. "The loser is Hu."
That Mr. Jiang has been able to insert himself so boldly shows how diluted power has become at the apex of the Communist Party, just as policy makers and intellectuals from all quarters say the nation needs strong leadership to guide it through a period of a slowing economy and rising social discontent.
Some supporters of Mr. Jiang say his involvement might give greater confidence to policy makers who could prove more amenable than Mr. Hu to loosening the hold of state-owned conglomerates in some crucial sectors, like finance and transportation, and also more inclined to establish a credible legal system that operates with a degree of autonomy from the party.
Such steps could inject vigor into the economy, while also signaling modest steps toward accountability demanded by China's expanding middle class.
Even so, Mr. Jiang's return to the center of party politics also exposes fundamental weaknesses in a system that relies on factional alliances and aging patriarchs to make crucial decisions.
China's ambitions to rise to be a modern global power remain yoked to a secretive political system in which true authority resides in hidden recesses. That could spell trouble for Mr. Hu's presumed successor, Mr. Xi, who has yet to establish his own credentials as the party's ultimate authority. When the congress ends next week, there will be 20 retired Standing Committee members, most of whom expect some say in running the country and appointing allies.
Mr. Jiang does not possess the indomitable behind-the-scenes power once held by Deng Xiaoping, who ushered in market reforms after the death of Mao Zedong. But a year of division and uncertainty has created openings for Mr. Jiang to shape important decisions.
"The atmosphere seems very tense," said Christopher K. Johnson, a former C.I.A. analyst now at the Center for Strategic and International Studies, who recently visited Beijing. "The problem is that there's no senior figure in charge — there's no revolutionary elder to act as arbiter and manage the different groups."
"My sense of the games that Jiang is playing is, 'This is my last hurrah, and I want to show that I still matter,' " Mr. Johnson said.
Mr. Jiang retired as party secretary in November 2002 and stepped down as state president the following March. He remained the chief of China's military until late 2004, which led to impatience among many party officials. His relationship with his successor has been a delicate one, shaped by the fact that Mr. Hu was put on the path to the top leadership by the party patriarch, Mr. Deng, leaving Mr. Jiang with no independent choice over who would succeed him.