I'd put my feeling down here. I do not believe there was a conspiracy to have Trump shot and killed. For that to happen, everyone involved would need to keep quiet. Even before that, people would need to be recruited into the group. And that's tougher than it sounds. There's a difference between "I know you don't like Trump so will you help us keep him from running again" and "I know you don't like Trump so will you help us kill him." You'd have to be an excellent judge of character if you're able to pick out only the people who would say yes to the second question. If you're wrong once, then there someone out there who knows you're looking for people who are interested in killing Trump. So when there is an attempted assassination, those people who were approached and said no would have to wonder. That's when leaks happen. On top of the number of people you need, you also need the right people. You could recruit a bunch of mechanics but that doesn't keep the trigger of the sniper rifle from being fired at the assassin. You need to recruit counter snipers. In this case, probably 4 of them. Then you have to make sure only the people you recruited were on the schedule for that detail. There's a lot of logistics that would have to happen.
There's a less intense possible conspiracy. They didn't set it up for Trump to be shot but rather they let open the possibility that he could be shot. The above conspiracy would have to involve the shooter. This one does not. This doesn't guarantee a shooting but if one were to happen, this wouldn't stop it. Interestingly, this may be harder that the first one. You still need to do the recuiting like before but you also have to have the right team in place for multiple events.
In addition to the agency recruiting, you would need the assistance of local and state law enforcement to ensure they aren't protecting the security gaps you planned.
