Allow current and retired service members to purchase firearms using only their Government ID cards and background check

Active duty and retired Military have already been screened and deemed safe to handle weapons during their time in service. Because of this they should just be able to walk into a shop and purchase whatever firearms they want using just their Government ID for active duty and for retires / Members who left service their ID and a local background check to ensure they are still being good citizens. If we cant trust our current and former Military members who are trained to use weapons than who can we trust?