Not too sure about "was it not the absence of a proper rule of law and the use of kangaroo courts inventing trumped up charges that drove the Founding Fathers to the USA?".

If you mean the Pilgrim Fathers and such, they didn't go to America so much because they didn't want kangaroo courts, but rather because they wanted to run these themselves. The witch trials in Salem was just one example of this.

The drafters of the Constitution knew about that kind of stuff, and knew they weren't perfect - and they framed it in a way that was supposed to bind the hands of citizens of the new country against falling into those ways of thinking and acting.

Which has meant that kits only by acting in the teeth of the constitution and in contempt of its principals that the administration that is tottering to its end this weekend has been able to do these things.