1. This case squarely presents a question that has divided the courts of appeals. Mr. Munera-Gomez was charged with drug offenses and raised an entrapment defense, but the key witness whose testimony he needed could not testify without a grant of use immunity.

2. The courts of appeals are split on when the government violates the Constitution by withholding use immunity and thus causing an exculpatory witness not to testify. Use immunity allows a defendant to exercise his right to compulsory process, and compel a witness to testify, because the grant of immunity avoids any Fifth Amendment issue. See Kastigar v. United States, 406 U.S. 441, 453 (1972) (use immunity "prohibits the prosecutorial authorities from using the compelled testimony in any respect" (emphasis added)). But in the First, Second, Fourth, Sixth, Seventh, and Tenth Circuits, the governmen

Whether the Fifth Amendment and Sixth Amendment right to compulsory process require the government to grant use immunity to a defense witness whose exculpatory testimony is essential to the defendant's case, or whether the government retains discretion to withhold immunity based on legitimate prosecutorial interests even when doing so effectively prevents the defendant from presenting a complete defense