International protocols restrict the use, or have even created international bans on weapons, notably weapons of mass destruction (WMD). International conventions define what constitutes a war crime, and provides for war crimes prosecution. Individual countries also have elaborate codes of military justice, an example being the United States' Uniform Code of Military Justice that can lead to court martial for military personnel found guilty of war crimes.
Trends in recruiting 1975–2001 showing total numbers of enlisted recruits in all branches of US armed forces in light blue and percentage of recruiting goals met in dark blue. Percentage of recruits with at least a high school diploma is shown in gold, percentage with an above average AFQT in orange, and the percentage called "high quality", with both a diploma and above-average AFQT score, is in purple.
In the 2000s, women can serve on U.S. combat ships, including in command roles. They are permitted to serve on submarines. Women can fly military aircraft and make up 2% of all pilots in the U.S. Military. In 2003, Major Kim Campbell was awarded the Distinguished Flying Cross for landing her combat damaged A-10 Thunderbolt II with no hydraulic control and only one functional engine after being struck by hostile fire over Baghdad.