DAVOS, Switzerland  Even as Congress looks for ways to expand President Obama’s $819 billion stimulus package, the rest of the world is wondering how Washington will pay for it all.

Few people attending the World Economic Forum question the need to kick-start America’s economy, the world’s largest, with a package that could reach $1 trillion over two years. But the long-term fallout from increased borrowing by the United Stated government, and its potential to drive up inflation and interest rates around the world, seems to getting more attention here than in Washington.

“The U.S. needs to show some proof they have a plan to get out of the fiscal problem,” said Ernesto Zedillo, the former Mexican president who helped steer his country through a financial crisis in 1994. “We, as developing countries, need to know we won’t be crowded out of the capital markets, which is already happening.”

Mr. Zedillo said that Washington, unlike most other countries, had the option of simply printing more money, because the dollar was a reserve currency for the rest of the world.