Conspiracies exists. Grand conspiracies don’t.
A small group of people can get together to perform illegal acts. However, they are usually found out relatively quickly (Lincoln’s assassins were captured within a few months). It is the nature of conspiracies to fall apart, especially once an illegal act is performed. Someone blabs, or someone else makes a mistake.
However, the more people in the conspiracy, the harder it is for it to succeed. Something like the JFK assassination would have taken dozens, if not hundreds, of people. How did the people get recruited? Isn’t is surprising that, when that many people told about plans to assassinate JFK, no one thought it might be a bad idea? And if small conspiracies are usually found out within a short time, a larger one would be discovered even sooner, since there are more people involved, and too many weak links.
Dogface – it wasn’t treason to work on the Constitution – the US was independent and those there were duly appointed to make changes in the Articles of Confederation. It was treason to work on the Declaration of Independence, however.