Prosecutors want a federal judge next month to impose the maximum 30-year prison sentence on a former Illinois National Guard soldier who plotted to attack a military armory in his home state, saying in a new filing that “betraying one’s country while in its service is a particularly grave crime.”

Hasan Edmonds, 23, of Aurora, deserves the stiffest penalty available under the law because he violated the oath he took when he joined the National Guard to defend the United States against all enemies, a government sentencing memorandum filed Friday in Chicago federal court says.

Edmonds devised a plan for him to travel to the Middle East and join Islamic State fighters while his cousin, 30-year-old Jonas Edmonds, attacked the National Guard armory in Joliet. The goal, prosecutors say, was to kill as many as 150 people at the facility.

The filing calls Hasan Edmonds’ plot “a contemptible betrayal of both the Nation’s trust and his fellow soldiers.”