Does anyone believe that the JFK ination was a government operation?

I personally think that JFK was the last true president who freely express his concern for the American people and what they wanted. Also, I think the government has become so powerful after the JFK ination that all the other presidents after him are puppets with the government pulling the strings behind closed curtains. There was also a rumor going on after JFK's ination that Lyndon B. Johnson secretly helped the government to assassinate JFK so he can become president. All I have say is " What a tremendous loss for America and the world."