Gary DeToma was sentenced to spend the rest of his life in prison after he pleaded guilty to suffocating his 5-year-old son. Now he’s trying to convince the Georgia Supreme Court to allow him to withdraw that confession.

Prosecutors say DeToma killed his son, Gary Jr., in 2010 to apparently get back at his estranged wife while their divorce was pending. DeToma pleaded guilty to the crime in May 2012 to avoid the death penalty and was sentenced to life in prison without parole in 2012.

A month later, though, DeToma had second thoughts and tried to withdraw that guilty plea. His attorney said in court motions that DeToma had buckled to “unrelenting pressure to plead guilty” from his previous lawyer, who brought his mother and brother in from New York to try to convince DeToma why the guilty plea was in his best interest.

The Georgia Supreme Court will weigh the case Monday after a judge denied that motion to withdraw. DeToma’s attorneys concede in court filings that “a death sentence may have been nearly certain,” but said he may have had other legitimate reasons to go to trial.

“Nelson Mandela, for example, went to trial, admitted guilt, and explicitly announced at trial that he was prepared to die for his cause,” his attorneys said in briefs, invoking the late South African civil rights icon. “We do not think less of him today for having done so.”

Prosecutors urged the Georgia Supreme Court to reject DeToma’s claim. They said in court documents that the evidence against him was “overwhelming and undeniable” and that the legal record shows that DeToma entered his guilty plea voluntarily and without coercion.

“Of course he struggled with the decision,” the state argued in its legal pleading. “But ‘changing your mind’ is not a legally valid reason to withdraw an otherwise knowing and voluntarily entered plea.”