I4i paints a more dire picture. "The implications are gargantuan," said Loudon Owen, chairman of i4i. "The whole system for innovation in this country is predicated on the patent system. If patent rights are eroded to where there's no point in having a patent because you can't enforce it, that will disrupt policy and the practice of disclosure."

The resulting uncertainty could cause some inventors to decide against patenting their technology, which would mean others couldn't license the technology to build on top of, he said.

Microsoft did not reply to a request for comment for this article. In the past, it has said it is pursuing the case because it believes there are important matters of patent law that need to be properly addressed.

. Some make unusual bedfellows. Supporting Microsoft are Apple, Google and the Electronic Frontier Foundation.

Supporting i4i is a longer list, including 3M, Bayer, 19 venture capital firms, the U.S. government and six former commissioners or directors of the patent office.