Stevens now has a legitimate opportunity to complain that the government violated its discovery obligations. That argument is strengthened by the government's apparent decision to hide the witness.

Williams had been in Washington, D.C., preparing to testify, but prosecutors sent him to back to Alaska last Thursday, saying they no longer needed his testimony. Prosecutors didn’t alert the defense or Judge Sullivan that Williams was leaving town. Judge Sullivan said he was “flabbergasted” by the government’s actions.

The prosecution's response:

“We believed we disclosed exactly what we needed to,” [prosecutor Nicholas] Marsh said.

If Williams told prosecutors a story during trial preparation that significantly varied from a previous version of that story, the defense had a right to know about it. The circumstances suggest that prosecutors instead canceled Williams' subpoena and promptly shipped him to a different state.

Impact on the trial: so far, none.

In light of the developments, Stevens’s lawyers have asked Judge Sullivan to declare a mistrial or dismiss all charges. Judge Sullivan said he was “not inclined at this point” to take either action, but he indicated that he will recall witnesses who already testified and let Stevens’s lawyers question them again.

The prosecutors just gave Stevens a nice appellate issue. Why couldn't they just play by the rules?