Recently there has been a growing debate in Korea on criminal accomplice liability through neutral behavior. Several well written articles on this theme have already been published. However these articles are based primarily on German references. Thus, the author of this article strives to expand the boundaries of the debate by introducing to a Korean audience the court decisions and theories of American criminal law on the subject. A special mens rea problem in U.S. criminal law involves suppliers of innocent goods or services who act with the knowledge that the goods or services will be used to commit a crime. The main issue is the question of whether knowledge that one's behavior facilitates someone else's criminal conduct is enough to establish criminal liability, or if purpose should be required. Courts differ sharply over whether such knowledge suffices to impose accomplice culpability. In United States v. Peoni, the Second Circuit ruled that nothing less than true purpose suffices for accomplice liability. After the Peoni case, the majority of US courts have followed the approach of the Peoni court. The Model Penal Code also limits accomplice liability to instances in which there exists the purpose of promoting or facilitating the commission of an offense. During the U.S. debate various compromises have been suggested. Rather than changing their complicity standards, some jurisdictions including New York have responded by enacting criminal facilitation statutes that penalize knowing assistance as a separate crime. The author of this article argues for a test that balances the conflicting interests of the vendors to freely engage in gainful activities without policing their vendees, and the interest of the community in preventing behavior that facilitates the commission of crimes. The author agrees with the opinion that the freedom to engage in legal business enterprises should be protected. Thus, for example, a seller or provider of innocent goods or value-neutral services capable of legal and illegal usage should, arguably, be able to rely on each vendee/user to independently decided on whether to use them for legal or illegal activities or purposes, and such vendors should, therefore, not be punished as accomplices.