Microsoft has filed its rebuttal of the US government's most recent court filing in the ongoing antitrust trial. This is the penultimate moment of the case before oral arguments from both sides regarding how existing antitrust laws should be applied to Judge Jackson's findings of fact occur on February 22nd.

Microsoft stands accused by the US Department of Justice (DOJ) and 19 US states of illegally using its dominance in PC desktop operating systems to try to quash competition in other areas, such as the market for Web browsers.

Microsoft's rebuttal tries to deconstruct the government's earlier filing with numerous examples of case law and other pointed criticisms of the way the DOJ has backed up its case. The software maker says the DOJ sought to apply out-of-context passages from decisions involving different market circumstances.

"By lambasting Microsoft, plaintiffs apparently hope to draw attention away from the flaws in their case," the Microsoft rebuttal said. "Time and again, plaintiffs' only support for bold pronouncements about applicable legal principles is a citation to their own proposed conclusions of law - which themselves contain little in the way of legal authority."

The US government has argued that Microsoft violated antitrust laws and that the company in its conclusions of law filing a week ago ignored the substantive issues of the case (see "DOJ condemns Microsoft")

DOJ case is wrong The software vendor's brief filed yesterday says the government's tying claim involving the integration of Microsoft's Internet Explorer Web browser and Windows operating system fails because the Windows 98 OS is a single, integrated product. Microsoft claims it is not forcing any customers to purchase a second distinct product, and the alleged tie does not foreclose a substantial amount of sales of the allegedly tied product.

The company also argues that Microsoft's license agreements with PC manufacturers are not an unlawful restraint of trade, claiming the DOJ's attempted monopoly claim flies directly in the face of settled cases. Microsoft has said all along that it has not engaged in illegal anticompetitive behaviour.