The power held by a Defense Engineer varies. For projects that they work on, Engineers can gain a decent amount of power, especially for those working beneath them. As an Engineer's security clearance increases, their power increases. But so does the need to keep quiet.
The sense of power, however, can be astronomical. Creating targeting systems that can pop a zit on a guerilla warrior's forehead with a single shot is pretty impressive. There are also the bombs that can level an entire city. Having that type of power in an AutoCAD blueprint can be exhilarating, especially when it achieves a major military objective or saves American lives. It's definitely a better story than the one told by automotive Engineer at the end of the bar who goes on and on about his new windshield wiper system.
At the end of the day, however, a Defense Engineer works for the United States government and, as such, must follow certain rules and protocols. They also have a very rigid power structure that they fall into and definitely know their place within the hierarchy. Combined with the fact that someone from the CIA or NSA likely has their phone tapped and periodically runs background checks on everyone they know, maybe the amount of power they have isn't so good after all.