From the Atlantic Council. Headlines are:

• The unipolar world of the 1990s, when the United States was the world’s sole superpower, is definitively over and will no longer be a realistic option for any president.
• An absolute United States’ decline is not inevitable, but an open conflict with China increases those risks considerably.
• A deep economic reversal in China could trigger a widespread economic meltdown that leads to a worst-case scenario of slower growth and a return to protectionism and political destabilization.

No real surprises, really.

Full report (pdf) here