“We’re not going to get very labor-intensive, relatively low-skilled jobs in America, and I don’t think we want them,” said A. Michael Spence, a professor at New York University and Nobel laureate in economics. “But sometimes it makes sense to have a little help developing technologies that will make us competitive. And sometimes public support for upgrading workers’ skills makes sense.”

“The best we could possibly get is continued modest growth in manufacturing jobs,” said C. Fred Bergsten, director of the Peterson Institute for International Economics, a research group in Washington.

Mr. Bergsten noted that manufacturing continued to become more efficient, meaning companies needed fewer and fewer workers. American manufacturers produced roughly the same amount of goods in 2010 as they did a decade before, but they did so with six million fewer employees on their payrolls. Mr. Bergsten also argued that sending jobs to other countries continued to make sense for many global firms. “You’re trying to buck two major trends,” he said.

Some economists also questioned whether Washington should be giving manufacturing a hand at all.

“It’s totally implausible to think that there’s going to be a surge in manufacturing jobs,” said Lawrence F. Katz, an economist at Harvard. Broader measures to improve American infrastructure and education, he said, would be more effective in creating middle-class jobs.

But the White House says that manufacturing offers significant potential for new jobs — jobs that require more skills and offer better pay than the assembly lines 30 or 40 years ago. And it says that even modest incentives might make a difference.

To that end, the administration has put together a far-ranging set of proposals: cutting taxes for manufacturers that produce goods in the United States, taking away tax breaks for businesses that move jobs offshore, doubling a tax deduction for makers of high-tech goods, providing support to businesses investing in areas where factories are closing, expanding worker training programs and creating a new task force to better enforce trade rules and intellectual property rights. Closing a loophole that allows companies to shift profits abroad would pay for the tax credits, the White House says.

It all adds up to what economists might call an industrial policy, the out-of-favor practice of using tariffs, taxes and other measures to help a particular industry. The White House avoids the term because it implies that the government is picking winners and losers. It argues that its proposals are a moderate plan to aid businesses deciding whether to move jobs overseas.