A writ of coram nobis is a legal remedy in a court of law that petitions the court to vacate a judgment as a result of a factual error or omission. For purposes of vacating a conviction in a writ of error coram nobis, the error or omission is not considered as one of the immigration consequences of a plea. A writ of error coram nobis is often the last resort used to reopen a case for fundamental errors of fact or law. For instance, where on the account of duress, fraud, or other fact overreaching the free will and judgment of a defendant where he or she is deprived of the right of a trial on the merits, the court in which he or she was sentenced may after judgment and after the time for appeal has passed, and if a coram nobis motion is seasonably made, the court may grant him or her the privilege of withdrawing his or her guilty plea.
In order to vacate a conviction with a writ of coram nobis the defendant has to show that at the time of the plea, he or she was unaware of the possible immigration consequences of his or her plea, that he or she would not have pled guilty or nolo contendere had he or she known of the possibility of deportation or other immigration consequences, and that his or her motion was brought with reasonable diligence upon discovery of true facts. It is important to note that this exceptional remedy applies only to a strong and convincing showing of the deprivation of legal rights by extrinsic causes.