Opine,
This was a professional hit on Trump
Two backpacks each with ceramic tiles. A go pro. An AK style sniper rifle (likely an AR-15) and a convenient witness to snap the picture.
Here's how it works;
The two backpacks are there to narrow return fires ability. With those bags hanging between the rifle it limits the ability of the secret service to get a clear shot should the assassins first shot miss. Those bags allow him to take the needed shots to complete the job while blocking his head and face. Without a direct head on view of the shooter return fire isn't as successful.
The go pro is there to record proof of death. Either through live stream or through a drop site.
The rifle itself is designed to be something anyone could get in order to make this look like some radical did it.
Finally the witness. They did their job. They had one job, hear shots, see the assassin get in the suv and take the picture. They planned on the assassin making a getaway but needed to ensure he was caught and disposed of. Unfortunately what they did not plan for was that the shots fired were from the secret service and not the assassin. The witness doesn't know this though so they take the pic thinking the job is complete. Without that pic this guy doesn't get caught.
This was so clearly planned by a professional.