Falls under their (somewhat) outdated doctrine of self-sufficiency.
Brett
There is also a bit of history behind them too. They were the only ones to operate 'tactical' EA assets in the beginning in Vietnam, starting with the EF-10 Skynight (http://www.globalsecurity.org/military/systems/aircraft/f-10.htm) . They were also the impetus behind the development of the EA-6A Intruder (http://home.att.net/~jbaugher4/newa6_5.html / http://www.bubbamoose.com/a6.html) . The Navy used the EKA-3 (http://www.a3skywarrior.com/gif/f8-a4-a3.jpg) and the Air Force used the EB-66 (http://home.att.net/~jbaugher2/b66_1.html / http://www.flygplan.info/images/Douglas_EB-66_Destroyer.jpg) (same basic design) for EA for most of the Vietnam War. The EA-6A could get a lot closer to the fight than the relatively large EKA-3/EB-66's and could avoid getting shot down better. The NVAF learned early on what the EKA-3's and EB-66's were doing and went after them and actually shot down a handful of EB-66's (remember Bat 21?), pushing them further away from the fight and making their jamming less effective. Which is why the Navy developed the EA-6B and the Air Force developed the EF-111, based on their respective primary strike/attack aircraft platforms of the day (EA-6B's made their combat debut with VAQ-132 in 1972).
So the Marines have a a deep history in tactical aviation EA, pioneering where the Navy and the Air Force lagged. Fortunately the Navy still remembers those lessons but the AF seems to forget their history, as usual......

P.S. I have to credit the book "Iron Hand: Smashing the Enemy's Air Defences" http://www.amazon.com/gp/product/1852606053/104-1997672-4602308?v=glance&n=283155 . I figured when I got to Prowlers I might as well learn some of the history of EA and it is a great book for that, if you are into that kind of stuff.......and want to show off some mad knowledges on AW.......
