The phrase "Asleep at the Switch" applies in spades:
PS. Definition is:
To be failing to attend to one's responsibilities or duties; to be inattentive to that which is important or for which one is responsible. Lots of folks were asleep at the switch it seems, but bottom line is the final failsafe for that happening belongs to the Secret Service and by default to the Director. A fish rots at the head.
How about "Andy Goes to Raleigh"?
This is almost like the Andy Griffith Show episodes where Andy goes out of town on business, and leaves Barney Fife and Goober in charge. The two Deputies end up locking themselves in a jail cell, while some bad guys move in and break into the Mayberry Savings Bank. Fortunately, Andy always gets back into Mayberry just in time to catch the bad guys and save the day.
It's a funny theme on a sit-com, but it isn't funny at all when a 20 year old gunman is able to get a close clear prone rifle shot at Trump an hour after he has been identified as suspicious, and is further identified as a bona-fide threat who is pointing a rifle at a Presidential candidate. He should never have gotten that far. He should have been stopped right then and there, long before Trump and two others got wounded, and two young girls were left with the nightmare of being sprayed with their heroic father's brains and skull fragments. This is one of the most sickening failures imaginable.
Even Barney and Goober couldn't blunder so badly. No one would believe it, which is why there are so many valid questions that are not being answered. I would feel a lot better if the Democrats in Congress and the Media were serious about getting the whole truth, like right now... not after some vague report in 60 days, and a whole lot of trying to pin the blame on local cops and a lack of communications. But instead, we have Democrat Congressmen using this tragedy to attempt to enact more Gun Control legislation, and we have members of the Liberal Left Media saying it was an elaborate hoax staged by Trump to win sympathy and support. We also have a whole bunch of conspiracy theories... some of which might well have basis in fact. I am not confident we'll ever know the truth. Certainly not from anyone in this Dept. of Justice.
Yesterday, the Secret Service Director testified under Oath that there were snipers positioned in two of the three windows with an overview of the mildly sloped roof where the shooter was able to climb with a rifle, and move around undetected by security. Today we have the Pa. State Police Commissioner saying those assets inside the building left that post to locate the guy who was identified as suspicious nearly a full hour earlier. If Kimberly Cheatle knew about that lapse, and she should have, then we can start with a perjury charge instead of a predictable knee-jerk Democrat race to attack our 2nd Amendment Rights. Sometimes just resigning with a nice fat pension is not enough.
A fish does indeed rot at the head. But the rotten head in this case is a couple notches above Kimberly Cheatle.