Improper Plea Deal Promises occur when a prosecutor makes, withholds, or manipulates plea agreement terms in a way that misleads the defendant, undermines voluntariness, or violates constitutional and ethical standards. This includes promising outcomes the prosecutor cannot deliver, concealing material consequences of a plea, or reneging on agreed terms.

**Scope:**

- **False or Misleading Assurances**: Promising reduced sentencing, probation, or dismissal of charges when such outcomes are outside prosecutorial authority or not legally possible.
- **Omission of Material Consequences**: Failing to inform defendants of collateral consequences (e.g., immigration status, sex offender registration, loss of parental rights).
- **Breach of Agreement**: Reneging on concessions offered in exchange for a guilty plea, or introducing new conditions after the plea is entered.
- **Coercive Leverage**: Threatening harsher punishments or unrelated prosecutions solely to extract a plea agreement.

**Examples:**

- Telling a defendant that a plea will prevent deportation, knowing immigration authorities retain discretion to remove them.
- Promising probation but recommending incarceration at sentencing.
- Failing to disclose that a guilty plea will result in mandatory registration or loss of professional licenses.

**Related Standards:**

- **Santobello v. New York, 404 U.S. 257 (1971)**: Prosecutors must honor promises made in plea agreements.
- **Mabry v. Johnson, 467 U.S. 504 (1984)**: Plea bargains must be voluntary, knowing, and intelligent.
- **ABA Model Rule 3.8**: Requires prosecutors to ensure fairness in charging and plea negotiations.
- **Fed. R. Crim. P. 11** (and state equivalents): Mandates disclosure of plea consequences and voluntariness.

**Consequences:**  
Improper plea deal promises can result in withdrawal of pleas, reversal of convictions, professional discipline, suppression of evidence obtained through coerced pleas, and civil liability.