So why do you believe some conspiracy theories and not others? Worth thinking about.
A combination of positive evidence; dearth of negative evidence which should be there; and how something unusually profits someone.
We started this whole thing by asking if 9/11 was a conspiracy at the level of what actually happened in terms of things colliding, exploding, burning, falling down, etc.
There are strange things in the material part of 9/11. But the strangest things, by far, are in the authorship and reactions. That is where I focus my conspiracist views.
To put this in perspective, how many cases do you have of world powers that have not engaged in lying?
So, given the precedents, should I question their claims, or should I buy everything they say? Oh, yeah, it's better than folks just deciding for themselves what's true. Obviously.
Supposed Soviet military superiority was the fuel for a lot of military spending in the US, especially in the Reagan years. There was a mix of lying, self-delusion, and true belief. Along with lobbying from defense contractors and the military.
You didn't have to believe the USSR was militarily superior to the US. All you had to believe was that it was close enough to put up a good fight (and it was) and that it was willing to be the aggressor against the West (which is more questionable, but was never conclusively negated).
Moreover, Reagan, or his entourage, realized that a military escalation would break down its economy and cause it to negotiate with the West. A calculation which worked.
Governments have also had plenty of secret intelligence that was correct.
And which in a case where you were risking the lives of thousands of American and allied troops, and the stability of a whole region, they had the obligation to show the public. It was far from a trivial affair.
However they are formed, the opinions of ordinary voters matter too. Lots of Democrats approved of the war in Iraq despite private doubts for the simple reason that it was popular with the electorate to do things to avenge 9/11, and resisting Bush was considered a political liability. Sometimes the elite trembles in the face of popular opinion -- and Trump's hold on power is the most dramatic case.
Resisting Trump is also a political liability, and yet Democrats are doubling down on their opposition. How does that work?