The US Military will merrily chase any proposal that promises them bigger guns, and most certainly chases after the proposal that promises them an ultimate weapon. Such a situation occurred during the development of the bomb during World War II. Money is no object. Massive and brutally enforced secrecy campaigns have and do occur.
So given past history, the HAARP project could indeed be real, confirming the rumors that abound. However, HAARP is not a real project, and the tale has simply been put forth in order to afford a cover for other activities. The US Military is deeply embarrassed by their past involvement with Service-to-Self aliens, an involvement which is rapidly ending but nonetheless lingers on. As anyone who has gone through a divorce will tell you, staying married might have been the easier route.
We will not detail the process, as by the Rules of Engagement we must at present keep from interfering with that process. However, HAARP has been put forth by humans wishing the populace to have a palatable explanation for various underground phenomena, and since those in the Service-to-Self had nothing to do with the HAARP campaign we can tell you about it.

Because the rumors spreading about put aliens in control of underground activities, the anxiety level of the populace was increased. As with most alien/human activity, humans want to believe they are in charge, as indeed they are. But some of the rumors put forth by humans wanting the populace to keep aliens at arms length had given a distinctly opposite impression - human body parts floating in vats and the like. MJ12, as with other arms of the government, does not always work as a unit, and has at times pulled in different directions. This was one such instance. To correct the misimpression, MJ12 cooked up the HAARP mystique. Since activities in association with Service-to- Self aliens included strange low frequency sounds, HAARP took on that aspect. Since aliens had been known to create blackouts and MJ12 wanted the illusion of a human hand at the switch should this ever happen again, HAARP took on this aspect also.

HAARP does not exist, but as secret programs can not be proved or disproved, this issue will never be settled. Since the public has given credence to HAARP, it is likely to take on extra baggage, becoming, on paper anyway, a larger program. But like the Wizard of Oz, it is not at all what it seems.