Wargaming a hostile takeover of a Western Government: Part 1

And some things that should not have been forgotten were lost. History became legend. Legend became myth. And for two and a half thousand years, the ring passed out of all knowledge. Until, when chance came, the ring ensnared another bearer. The ring came to the creature Gollum, who took it deep into the tunnels under the Misty Mountains, and there it consumed him. The ring gave to Gollum unnatural long life. For five hundred years it poisoned his mind; and in the gloom of Gollum's cave, it waited. Darkness crept back into the forests of the world. Rumor grew of a shadow in the East, whispers of a nameless fear, and the Ring of Power perceived. Its time had now come. -Galadriel J.R.R Tolkien, The Lord of the Rings

I want to conduct a thought experiment: how could the US fall into dictatorship and / or totalitarian rule with the current sociopolitical background for the country?  What (friendly) forces are likely to slow, resist, or attenuate that movement.  Let's paint some scenarios.

Background: Extreme economic stress, perceived social injustice, inflation, war (Iraq, Afghanistan, etc.)
Watch the following video starting at 5:00:


Disclaimer: All of the information and ideas of "evil people" that follow are completely fictional and are not intended to apply to anyone currently serving in government office.  Any similarities are purely coincidental and unintended.

Assume a purely evil individual with aspirations for absolute power is elected into some position of government, to speed things up in this scenario, we'll assume they have been elected Speaker, Senate leader, Fed Chairman, President or PM.  How could they completely obliterate the remaining constitutional defenses of the people, and make themselves dictatorial ruler?  In the case of this evil individual being elected office, or appointed to a position other than President, they would have an additional step to marginalize, imprison, impeach and /or move out of the way the sitting executive.  That would be a difficult task, but not without historical precedent in world history. 

This scenario overlooks another important possibility.  What if a perfectly average politician is thrust into a scenario where the overall environment is severe social and economic stress, and in which the checks to his or her use of power are dismantled and removed, as is currently in process?  That individual imagines they can "engineer" a solution.  The only task remains to get rid of any obstacles to implementation of that "solution".  They rationalize and believe the ends justify the means.  Is the dictator evil, or does the absolute power make the dictator evil, or some combination?  Most importantly, does the dictator choose the nation, or does the nation choose a dictator? Both?

How would this individual get such popular support?  I highly recommend watching the whole movie that was linked above, "Die Welle".  Here is the trailer:

 In my next post I will discuss the resistance to such government takeovers, and strategies for a totalitarian ruler to attenuate those forces.