Hill's execution would be a clear violation of the Eighth Amendment ban on cruel and unusual punishment, as ruled by the US supreme court itself in Atkins v Virginia.
Hill's execution would be a flagrant violation of the US supreme court's own ruling in 2002, Atkins v Virginia, that banned the death sentence for prisoners classified as "mentally retarded".
Ferguson's legal team, backed by a raft of prominent legal and mental health organisations, had appealed to the nation's highest legal panel to step in on grounds that the execution would be a flagrant violation of the Eighth Amendment of the US constitution that bars "cruel and unusual punishment".
Officials at the news conference said the crimes eligible for execution would be a fraction of those that drew the gallows or firing squad under Mr. Hussein, involving more than 120 provisions in Iraq's criminal code, many of them essentially political crimes.
Because Williams is obese, his lawyers argue that his execution would be "a slow, agonizing death experienced as suffocation".
But Indonesia's attorney general later confirmed that the nine death row convicts would be executed as planned, without giving an indication of when the executions would be likely to take place.
A second batch of executions would be held later this year and also target drug smugglers, he warned.
A spokesman for Prasetyo, Tony Spontana, told Guardian Australia the executions would be after the Asian-African conference in Jakarta from 19 to 24 April, but could not confirm a timeframe beyond that.
Although his efforts had seemed to have won them a reprieve last month, the Chinese ambassador to the Philippines, Liu Jianchao, said last Thursday that the executions would be carried out "sooner or later".
