The Glock, preferably in 9mm, but I wouldn't pout if they chose .40 or .45.  It's an idiot proof firearm, just so long as you beat it into your troops' heads to keep their fingers off the damn trigger until they are ready to fire.  If you absolutely HAVE to have an external safety (which is unnecessary on a Glock as long as the above rule is followed), I understand that Glock designed a pistol with an external safety a few years ago so it could compete for US Army pistol trials.  Glocks are rugged, reliable, accurate, and have a long track record of service........not to mention a pretty impressive body count.