Any evidence that Microsoft corrupted the ISO voting process would strengthen the Commission's antitrust case, but the case would still be strong without such evidence, according to Thomas Vinje, legal counsel for the European Committee for Interoperable Systems, a trade group whose complaint forms the basis for part of the latest Microsoft antitrust probe.

"Granting ISO status to OOXML doesn't begin to resolve the competition law questions the Commission is looking into," Vinje said by telephone. ECIS members include some of Microsoft's biggest rivals in the computer industry: IBM, Sun and Oracle.

The Commission declined to comment on any impact the ISO vote would have on its antitrust case.

"Even if the votes were legitimately won - which I doubt - OOXML is not an open standard because it isn't fully implemented on competing platforms, and its future shape is subject purely to Microsoft's control," according to Vinje.

Jan van den Beld, a standards expert with the trade group CompTIA, disagreed, arguing that hundreds of technical experts from the national ISO branches would ensure that OOXML "will not mutate to the benefit of a single vendor." CompTIA is a longtime ally of Microsoft in its antitrust battles with regulators. Van den Beld's comments were made in a statement Tuesday.

The ECIS complaint that sparked the Commission's latest antitrust charges claims that Microsoft has unfairly withheld information from companies that wanted to make products compatible with the word processing, spreadsheet and office management tools in Microsoft Office. By withholding the interoperability information, Microsoft has effectively kept rivals out of this lucrative market, ECIS argues.

Confusingly, the Office Open XML format being assessed by the ISO "is not what Microsoft implements in the Office suite," Vinje said, adding that "If you implement OOXML, you don't get interoperability with Office."

"ISO status for OOXML is certainly not the end of the story for the Commission's antitrust case," he said.