Four former Blackwater security guards face decades in prison when they are sentenced Monday for their roles in a 2007 shooting of Iraqi civilians.
Three of the guards- Dustin Heard, Evan Liberty and Paul Slough- face mandatory, decades-long sentences because of firearm convictions.
A fourth, Nicholas Slatten, faces a life sentence after being found guilty of first-degree murder.
The men were charged in the deaths of 14 Iraqis at Nisoor Square, a crowded traffic circle in downtown Baghdad. The killings caused an international uproar, and the men were convicted in October.
Prosecutors have described the shooting as an unprovoked ambush of civilians, though defense lawyers countered that the men were targeted with gunfire from insurgents and Iraqi police and shot back in self-defense.
The lawyers are expected to argue for mercy Monday by saying that decades-long sentences would be unconstitutionally harsh punishments for men who operated in a stressful, war-torn environment and who have close family ties.
The firearms convictions alone carry mandatory minimum sentences of 30 years in prison. But the government is seeking sentences far beyond that, partly because they say the men have never shown remorse or accepted responsibility.