A California judge denied Microsoft’s request to subpoena rivals Sun Microsystems and Oracle in an order issued Wednesday. Microsoft was seeking access to documents from the U.S. vendors in relation to its ongoing battle with the European Commission over whether the company has complied with a 2004 antitrust ruling.

In a six-page order, U.S. District Court for Northern District of California Magistrate Judge Patricia Trumbull granted motions from Sun and Oracle to quash the subpoenas and vacate the prior order that had granted Microsoft permission to serve the subpoenas.

Microsoft and the commission have been at a standoff since late last year when the European body ruled that Microsoft had violated the 2004 decision. The two parties are facing off in a two-day hearing beginning Thursday to debate Microsoft’s compliance with the ruling. Should no progress be made, Microsoft faces maximum daily fines of 2 million euros (US$2.4 million), backdated to mid-December, until the commission deems it is complying with the 2004 ruling.

"Microsoft has attempted to cast the DG-Competition [the European Commission’s Directorate General - Competition] as an ‘adversary,’ " Trumbull wrote in the order. "In the light of the nature of the European Commission, that label is incorrect. As a matter of comity, this court presumes the neutrality of both the DG-Competition and the European Commission." She also contrasted the "adversarial" nature of the U.S. legal system with the "inquisitional" nature of the civil law system of which the European Commission is a part. In the latter, the judicial officer is more actively engaged in evidence gathering, Trumbull noted.

The judge described the subpoenas as constituting "an attempt to circumvent specific restrictions the European Commission has placed on Microsoft’s right to obtain certain kinds of information." She added, "As a matter of comity, this court is unwilling to order discovery when doing so will interfere with the European Commission’s orderly handling of its own enforcement proceedings."

Earlier this month, Microsoft asked the court in California and two other U.S. courts to grant it permission to serve subpoenas on Sun, Oracle, IBM and Novell to produce all documents containing correspondence the four companies had engaged in with the commission.

Microsoft also filed requests for subpoenas in New York and Massachusetts; those cases are still ongoing. Sun and Oracle have their headquarters in Santa Clara and Redwood Shores, Calif., respectively, while IBM is based in Armonk, N.Y., and Novell is based in Waltham, Mass.

The commission’s 2004 ruling found Microsoft guilty of anticompetitive behavior for not allowing its competitors’ server software to fully interoperate with PCs running its Windows operating system and for bundling its Media Player software with Windows.