To amend title 18, United States Code, with respect to terms of imprisonment and supervised release following revocation of a term of probation or supervised release.

Amends the Federal criminal code to allow the court, in determining the sentence to be imposed in the case of a violation of probation or supervised release, to consider guidelines or policy statements issued by the U.S. Sentencing Commission.

Revises provisions regarding the revocation of probation to: (1) authorize the court to resentence a defendant who violates a condition of probation at any time prior to the expiration or termination of the term of probation; and (2) provide for mandatory revocation for possession of a controlled substance or firearm or refusal to comply with drug testing imposed as a condition of probation and resentencing of the defendant to a sentence that includes a term of imprisonment.

Directs the court to revoke supervised release and require the defendant to serve in prison all or part of the term of supervised release authorized by statute for the offense that resulted in such term of release without credit for time previously served on post-release supervision if the court finds that the defendant violated a condition of supervised release, with exceptions. Provides for mandatory revocation of supervised release for possession of a controlled substance or firearm or refusal to comply with drug testing imposed as a condition of supervised release.

Authorizes the court to include a requirement that the defendant be placed on supervised release after imprisonment when a term of supervised release is revoked and the defendant is required to serve a term of imprisonment less than the maximum authorized. Specifies that the length of such a term of supervised release shall not exceed that authorized by statute for the offense that resulted in the original term of release, minus any term of imprisonment that was imposed upon revocation of supervised release.