can someone who's a little more knowledgeable explain why you'd even want to impersonate a cop? it's not like it's extremely hard to just become one and then you're not committing a crime.
It varies from person to person, obviously, but generally I would agree with the other poster who said many of these people use it as a sort of power trip. They want to use it to control people, or just to make themselves feel in control.
There are other reasons though, mental illness and delusional thinking might be one, it may be a case of someone wanting the feeling of being admired without doing the work. Intermix this with someone who enjoys thrill seeking and is a pathological liar too.
Jeremy DeWitte is probably a little of column A, B and C.
It's clear in his interactions he enjoys wielding power over others, he likes bossing people around and barking orders.
Him saying he jumped at Fallujah would indicate wanting to have people admire him as this confers nothing in terms of granting him personal authority.
Its hard to say exactly what is wrong with Jeremy, mental illness, personality disorder, delusional... All of the above? There is something that doesn't tick right in his head though, and I think that's part of why he does this.
Additionally, he's a thrill seeker, noone drives at the speed and in the manner he does without that being part of their make up.