It doesn't have to be monolithic. All it has to do is have the government controlled by Christians with no protections for others. Those in charge then do what they believe is right according to their religion, which can be disastrous for others not of the same exact belief. Again, look at the recently deposed Charles Taylor. Going further back, it gets worse, to the point where you were killing and deporting other Christians over differences in doctrine.
This is somehow seen as a "threat." An all-out assault is currently being waged to strip Christians of the ability to speak, and participate in government, through the use of activist judges and groups like the ACLU. The opinions of Christians are slowly being redefined as "hate speech."
It is of course wrong to attempt to silence Christians as much as it is those of other faiths. I support Fred Phelps' right to picket gay funerals, however detestable I find the tactic to be. However, I doubt a Fred Phelps in charge would even allow gays to protest his policies.
Like I said - the only abliity any Christian has to impose his will is through the appropriate channels of representative government, just like everyone else.
That's the problem. Our government isn't about imposing anybody's will on anyone else. The people are supposed to be free from the tyranny of the majority with minimal government intervention in their lives.
You want an example of people imposing their will on others through government? Just look at the anti-smoking nazis.