Can a defendant be convicted of conspiracy without any involvement in the conspiracy?

I nonetheless write separately, to express my concern that some of the quotations in Part II.A could be read, in isolation, to suggest that a defendant may be convicted without in any way participating in a conspiracy, if he simply has knowledge of the conspiracy and a connection to its participants. See Maj. Op. at 1086. That, of course, is not the law. See, e.g., United States v. Tran, 568 F.3d 1156, 116465 (9th Cir.2009) (reversing a conspiracy conviction because there was no evidence ... from which it could be inferredmuch less proved beyond a reasonable doubtthat [the defendant] participated in the conspiracy in any manner) (emphasis added).