The US Supreme Court on Monday limited new trials for felons convicted for being in possession of a firearm, limiting the retroactive application of its 2019 decision Rehaif v. United States.

The issue in Greer v. United States involved 18 USC §922(g), the federal law prohibiting felons from possessing firearms. Under the 2019 decision in Rehaif, the government had to prove both that a defendant knew he possessed a firearm and that he knew he belonged to a category of persons prohibited from possessing firearms in order to convict that defendant under the statute.

Gregory Greer and Michael Gary were separately convicted of being felons in possession of a firearm, prior to the decision in Rehaif. Greer was convicted and sent to prison, but he appealed the decision following Rehaif. Gary pleaded guilty to the charge, but, following Rehaif, the court held that the government had committed a structural error by failing to inform Gary that the government was obligated to prove that Gary knew he was a felon at the time of the offense. His conviction was vacated, and the government appealed.

On Monday, the Supreme Court held that, in these types of cases, an error based on Rehaif is not a basis for plain error relief unless the defendant “first makes a sufficient argument or representation on appeal that he would have presented evidence at trial that he did not in fact know he was a felon.” A defendant forfeits the claim of error if he has the opportunity to object but fails to do so.

In an opinion written by Justice Brett Kavanaugh, the court found that the errors occurred during Greer’s and Gary’s trial court proceedings and that the errors were plain. Greer and Gary respectively had to show that, if the district court had correctly instructed the jury, that there was a “reasonable probability” that he would have been acquitted or would have not pled guilty. The court found that neither carried that burden, as both had been convicted of multiple felonies prior.