It is getting harder to prop up the economy. Still, U.S. is in better shape than other countries, I think. When things go bad, economies of other countries suffer first. People in those countries would move their fund(wealth) to U.S.. As bad as U.S. economy is, many in the world believe that U.S. economy is more stable and robust than theirs. This is especially true among wealthy Chinese. U.S. would be the last one to go down because of these additional injection of foreign money. The downside is that, in some region, housing price may not go down even when local economy worsens.
This does not mean that U.S. economy is peachy. It is just that U.S. economy would be able to hang on longer than others.