OK, I'll play.
John F. Kennedy is officially killed by a sniper hiding in the Book Depository firing behind and above him, yet the kill shot comes from down and in front. According to video evidence - and more importantly the firm opinion of combat trained trauma surgeons in the ER of Parkland Hospital when Kennedy arrived - the kill shot enters through the throat and blows out the back of his head. Ergo, a second shooter. Or Oswald can curve bullets like Neo.
Lee Harvey Oswald had direct links to Organized Crime, Carlos Marcello of New Orleans in particular. He does pro-Communist work on behalf of Cuba, maybe. And most impressively, he flies to Russia and returns with a bride related to a KGB chieftain after defecting, his return to America paid for by the US government.
Lee Harvey Oswald has a direct link to the Mob, Intelligence, and works at the Book Depository; he is involved in some manner. Whether he pulls a trigger is academic, his role in this operation is as 'THE FALL GUY'. He is going to take the rap for what happens regardless of what he did or did not do.
The Mob has the shooters who can pull the trigger, and there are about two dozen prime suspects for who is standing behind the Grassy Knoll (Maybe Woody Harrelson's dad), and who is hiding in the storm drain at the curve in the road beneath the bridge that actually administered the kill shot (Handsome Johnny Roselli), to create a Triangulated Fire mandated on a professional hit of this nature. The Mob CAN pull the trigger, they can't silence a Federal Investigation. To the Mob, the US Goverment won two world wars and prints their own money - they don't tangle with the Feds. Ever! They'll kill Kennedy because he screwed them royally, but they aren't stupid enough to give that order without protection.
On November 22, 1963, in Dallas The Lone Gunman, Lee Harvey Oswald, kills Kennedy and is proclaimed from the heavens to be the sole perpetrator of the attack using doctored photos and questionable storylines.
Jacob Rubenstein is an associate of Momo, Sam Giancana, who is the Front Boss of the Chicago Outfit under Tony Accardo. Momo definitely rigged ballot boxes in Chicago at Joe Kennedy's behest, and he was theoretically involved in a three-way with JFK when he was a senator with a mutual paramour. This is personal to him. Jacob, aka Jack Ruby, is well known to Dallas police. Walking up to Oswald in a heavily armed basement Ruby does a Mob style hit, killing Oswald in plain sight on national TV before he can be taken to a quiet area and put to the question. Oswald's killer states he acted on orders from above and if he said any more his life was forfeit, if you can read between the lines.
The investigation is run by J. Edgar Hoover after he uses a peculiar circumstance to take over the investigation from the SS. And the stories of improprieties, witness badgering, threats, and evidence entered and lost followed by the peculiar deaths of so many tangential characters. The FBI can cover up the investigation, but they can't give a Go! order and they can't pull the trigger.
To me, the kill shot entering the throat and blowing out the back of Kennedy's head is the entire argument. Therefore, who gives the order?
The Mob will pull the trigger, but can't control the investigaion; the FBI can control the investigation, but can't pull the trigger AND control the investigation.
CIA?
The CIA has the only human being devious enough to pull the rabbit out of the hat: James Jesus Angleton, CIA director of Counter-Intelligence, who was humiliated by the Bay of Pigs because Kennedy pulled the airpower necessary for OPERATION ZAPATA / ZAPATA OIL (George HW Bush, where all the Cuban mission supply ships are code-named after his own family members) to succeed in its task. CIA has shooters of their own, and have existing relationships with the Mob forged during WWII and reformed during the CIA and Mafia's joint desire to 'Whack the Beard' - kill Castro and resume control of Cuba.
The Bay of Pigs screws Corporate America, enrages the US High Command, and makes the CIA look foolish. Kennedy's next directives will be a total housecleaning in the US intelligence community, which includes removing Hoover as director of FBI.
Angleton has direct connections with the Mob through Cuba, connections with Hoover since the formation of CIA, and motive. Angleton is like Heydrich, he can build the operational requirements to take out SA in one fell swoop; but neither can give the Go! order. It must come from above, such as Adolph standing in the Brown House telling Goebbels to call Goring and say 'Kolibri', unleashing the gathered storm.
Angleton builds the plan. The Mob provides the shooters. The FBI covers up the trail.
So you find the one individual in the US following the death of Kennedy who can protect CIA and FBI from on high following a highly controlled assassination in his own home state of Texas. That is the individual who - logically - can be the only one who gave 'THE' Go! order. Y'all.
Wait. Are you saying that Lyndon Johnson is the one who had jfk assassinated??