What is the test for reducing the sentence of a convicted criminal who was convicted of conspiracy to obstruct the course of justice?

Cleghorn argues that the district court erred when it found that Cleghorn reasonably could have foreseen the illegal acts of his co-conspirators, that he played only a minor role and that his sentence thus should have been reduced. The legality of a sentence is reviewed de novo. United States v. Turner, 898 F.2d 705, 708 (9th Cir.) cert. denied, 495 U.S. 962 (1990). We accept the district court's findings of fact unless clearly erroneous and give due deference to the district court's application of the Guidelines to the facts. Id.