I am not sure how to assess a pronghorn buck's rutting agressiveness.  I've seen them when they are in the rut and they are pretty territorial and chase off other bucks.  It is a little different than whitetail in sense that two bucks will square off and lock horns, but with pronghorn bucks, from what I observed it rarely comes to that...they just chase off less dominant bucks.

As far as the decoy, yes, they will approach it with menance in their eyes.  So using a buck decoy can be effective.  I don't know from personal experience, but I've seen cow decoys work on tv and on a previous thread we discussed an outfitter who used a horse to hide the hunter and sneak up on the pronghorn.

I can't tell your for sure how they'd react to a decoy as I haven't used one.  However, I've hunted them in the rut in Wyoming the last five years and they are very aggressive towards other bucks.  I've seen the dominant buck many times go chase away subordinate bucks that are bedded down and not even bothering the does.  I've seen as many as ten bucks in one group and at that point it get's a little difficult for the dominant buck to maintain control.  I would imagine you would have better luck if the buck you are after has the does all by himself or only another buck or two harassing the does.  

there a very agressive animal once you get close to them, one time hunting pronghorn my hunting partner shot this buck and it droped right in its place then we let it sit then came back for it and walking to it i he found it before me and i looked up in the weed the pronghorn jumped up and charged him and he jumped and the pronghorn ran around 60 yds and droped and it was died it was the crazyiest thing i have seen.

I agree with those that think they are about as aggressive as critters come once they are in the rut. They may not weigh very much but what they lack in size, they make up for in furry. I have seen them lock up and fight on many occasions. And it was one of the most impressive ungulate fights I have ever seen in my life. They were fighting on a ridge and one would push one 100 feet down slope, and then it would fight right back up. I could not believe the stamina that both bucks showed. The one that ended up losing and walking away did not look like he was in good shape. I actually took my doe out of this group. I am going to get that story written soon. I think you will have good success with all of your decoys. They respond well to buck decoys if they are rutting hard and the cow decoy should work just about anytime if the goats are used to seeing cattle.

Yep, they are very agressive during the rut and they will lock up in knockdown dragout battles just as described in the previous post.  Many times they will break off part or all of a cutter in their battles and they will definitely charge a decoy if they are bigger in order to run him off from their does.

The first couple of times I hunted them it was post rut and I didn't look them over well and ended up shooting bucks that had at least one cutter broken off. Very disappointing when you just waited years to get the tag.

Antelope locking horns doesn't really get the adreneline going like watching Elk, Moose or Big Whitetails.  Watching the energy they expend chasing each other to protect or steal a hot doe is crazy.  The speed and amount of terrain they can cover in 30 seconds blows my mind.  Their recooperation period can be very breif like two Big Horns Banging Heads and then they are ready to chase at full speed all over again.  Its amazing they have any energy to mate afterward.

I think they get very agressive...just as much as any other big game while rutting.  My wife and I watched two buck darn fight to the death durning the rut.  It was amazing to watch and those buck have got alot of power in the little bodies.  We came to the concusion while bow hunting over water in the rut the buck decoy DID NOT work as well.  The bucks chased the does so much that the does would not even come to water if another buck or the decoy was near the water.  We just stopped using the decoy and the does cam in and then with that the bucks would come even closer.