Going too far to the right or left is definitely a threat. The great thing about the US imo is that we are a nation of moderates.

The entire 20th century was a case study on the dangers of far right and far left wing political systems.

what do you mean by too far to the left? how is america going to the left? america is "the" right wing goverment.. there is a whole healthcare debate going on?

To give you some perspective. What counts as moderate in the US is, at best, center-right in Europe. Heck, a lot of Democrats would be considered center right over here. People like Bernie and Warren would count as moderate with, maybe, a tendency to the left. So your standard left wing politics in Europe would probably count as extremist in the US. Just as an example from the German capital: nationalization of residential buildings to prevent further rent increases. Or one, agreeably rather extreme, proposition from the youth wing of Germanies center left SPD was the nationalization of certain public companies to better share out profits to workers.