United States v. Fokker Servs. B.V., 818 F.3d 733, 742 (D.C. Cir. 2016) is the controlling case in the DC circuit. The DC COA held: “[T]he `leave of court’ authority gives no power to a district court to deny a prosecutor's Rule 48(a) motion to dismiss charges based on a disagreement with the prosecution's exercise of charging authority.”
“[T]he `leave of court’ authority gives no power to a district court to deny a prosecutor's Rule 48(a) motion to dismiss charges based on a disagreement with the prosecution's exercise of charging authority.”
The only reason the Fokker decision says Judge Sullivan can not deny the motion to dismiss is "a disagreement with the prosecution's exercise of charging authority." So, Judge Sullivan has room to argue that is not the reason he has so far delayed (not denied) the motion to dismiss. His arguments might include:
1. Either the current or the former prosecutors lied to me, and I am entitled to find out which ones lied before dismissing the case.
2. The DOJ is playing games by moving for dismissal because the Flynn interview was not "material" to an investigation, when I already held that it was material - based on the arguments DOJ made six months ago.
3. The DOJ is playing games by securing Flynn's agreement to withdraw his “motion to dismiss case for egregious government misconduct” on the same day the DOJ filed its motion to dismiss. They are not entitled to use dismissal as a way to cover up misconduct.
4. Even if the DOJ's misconduct with respect to Flynn was by the prior prosecutors, the current prosecutors effort to cover that up (rather than tell the court there was misconduct) is a separate form of misconduct that the Court must investigate.
The charges against Flynn are going to be dismissed eventually, but the suggestion that Judge Sullivan is out of moves is premature.