C'mon RA, you're better than that. If this was a conspiracy (it wasn't) it was the best kept secret of all time.
The position of Connolly in the limo has been well documented but conveniently overlooked by the conspiracy buffs.
http://mcadams.posc.mu.edu/sbt.htm
As you can see JFK is
not sitting directly behind Connolly (as
they would have you believe) but instead is situated behind and to the right.
Also and plus, Connolly's seat was lower than JFK's

Sadly, one crazy POS with a rifle was able to take down the POTUS.
It happened then, it happened 4.5 years later with MLK and then two months after that with RFK.
Refute as you see fit.