Someone should do a thread on "Psychology of the Everything's Just a Coincidence Theorists."
People are convicted of conspiracy all the time in this country. We have laws against conspiracy because we know from long experience that conspiracies happen.
According to the U.S. Government, two of our presidents were killed by conspiracies: Abraham Lincoln and John F. Kennedy.
The government convicted and hung several people for conspiring with John Wilkes Booth to kill Lincoln. The government adamantly insisted that Lincoln was killed by a conspiracy.
A select committee of the House of Representatives concluded that Kennedy was probably killed by a conspiracy. The chief counsel, his assistants, and the staff investigators made it clear in subsequent books that they were certain that a conspiracy killed Kennedy.
Also, there was a conspiracy to depose FDR. The plot was foiled before it could swing into action because one of the generals the plotters approached ratted on them. True to form, the government and the press denied there had been a plot, but subsequent research has refuted that cover-up.
http://www.ctka.net/pr399-fdr.html
Congressional Democrats posited a massive conspiracy involving Reagan, his national security staff, the CIA, and elements of the Pentagon in the Iran-Contra affair, and they noted that if Oliver North had shredded just a few more documents, the conspiracy may well have remained uncovered.
And on and on and on we could go.