(C)  Procedure.  Where a breach has been shown, the government bears the burden of persuasion to establish that defendant breached the plea bargain, and hearsay is inadmissible to prove this.[306]  The government may not, consistently with due process, unilaterally nullify a plea agreement.  It must instead establish, at a hearing, by a preponderance of the evidence (a) that the defendant breached the agreement, and (b) that the breach was sufficiently serious to warrant rescission of the contract.[307]  If a defendant claims a plea bargain has been violated, the court must grant a hearing on the question.[308]

[306] United States v. Verrusio, 803 F.2d 885 (7th Cir. 1986).

[307] United States v. Castaneda, 162 F.3d 832 (5th Cir. 1998).

[308] Mathews v. Eldridge, 424 U.S. 319, 333, 96 S.Ct. 893, 47 L.Ed.2d 18 (1976); United States v. Frazier, 213 F.3d 409 (7th Cir. 2000); United States v. Ataya, 864 F.2d 1324 (7th Cir. 1988) (breach by defendant who failed to identify co-conspirator).

Ninth Circuit

POST CON RELIEF " GROUNDS " BREACH OF PLEA AGREEMENT
United States v. Heredia, 768 F.3d 1220 (9th Cir. Oct. 8, 2014) (vacating sentence on grounds that the government violated the plea agreement by making repeated inflammatory references to the defendant's criminal history in its sentencing memorandum, in effect arguing for a higher punishment than it had agreed to recommend; the court reversed the sentence, not the conviction, since the defendant waived any argument the error invalidated the conviction itself).