In Hell with 47

[Thumpalumpacus]

To be honest, I'm rather ignorant when it comes to political affairs.

So, my first question is: how do the checks and balances fit in order to prevent a leader dictatorship?

They rely upon the good faith of the politicians running the system. Once we arrive at a point where one side or the other works in bad faith, the choice is either to prosecute or to watch the system fall down. America has chosen the latter.

Second, how do the intelligence agencies fit into preventing such a disaster to the country?

They don't.