But so far, Mr. Xi has offered almost no clues as to where he stands on overhauling the economy, while Mr. Li’s track record during his time as a provincial governor and party secretary suggests he is more of a risk-averse technocrat than a reformer.

For the moment, the world’s second-largest economy is drifting, as exports to Europe and the United States wane. Some economists even suspect that the official figure of an annual rate of growth of 7.6 percent in the second quarter is overstated; indicators like electricity generation are rising much more slowly. Moreover, part of the growth led only to producing stocks of unsold appliances, toys and coal that are piling up at warehouses and ports.

Still, Beijing has largely held back from the kind of prodigious investment in housing and public works that propped up the flagging Chinese economy during the global downturn. In an editorial published this month, People’s Daily, the party’s influential mouthpiece, conveyed the official view, saying the central government should resist the temptation to spend its way out of the slowdown.

In a speech this month at a World Economic Forum session in Tianjin, Mr. Wen agreed that the government was holding its fire, but said that it would step in forcefully if necessary. Beijing has a budget surplus of $158 billion, with $16 billion more in a reserve fund, he noted.

“We will use that money at a right moment for pre-emptive policy and fine-tuning to propel stable economic growth,” Mr. Wen said.

Local governments, alarmed by a slowdown they fear could lead to mass unemployment and the kind of sluggish growth that can dent political careers, have decided to take matters into their own hands. In recent months, a number of cities have proposed extravagant infrastructure projects they hope will be financed in part by newly liberalized bank loan policies.

Tianjin claims $236 billion will be spent in the petrochemical, aerospace and other industries. Xi’an, home of the famed terra cotta warriors, plans to invest tens of billions of dollars on nine new subway lines. In Guizhou, one of China’s poorest provinces, officials said they hoped to funnel $472 billion into tourism-related development.