WASHINGTON (AP) — The Supreme Court raised serious doubts Tuesday about a $399 million judgment against smartphone maker Samsung for illegally copying parts of the patented design of Apple's iPhone.

Justices hearing arguments in the long-running dispute seemed troubled that Samsung was ordered to pay all the profits it earned from 11 phone models even though the features at issue are just a tiny part of the devices.

But some justices struggled over how a jury should be instructed if the case is sent back to a lower court. Justice Stephen Breyer appeared to embrace a test proposed by Facebook, Google and other internet companies that would outline new limits on such damage awards.

Other justices seemed to favor a different test proposed by the Obama administration.