Christian thinkers have defined tyranny as the use of power to advance one’s own interests rather than the common good.
A tyrant doesn’t have to be particularly powerful. A small-town mayor who manipulates the town council to help herself and her friends is a tyrant, albeit a petty one.
A politician whose life is consumed with maintaining and advancing his power is a tyrant.
Insofar as American politicians always have an eye on the next election, insofar as they legislate and speak and act so they can keep their spot in the next round, they are using power tyranically.
In today’s America, that’s what all politicians do. That’s what politics is.
American democracy has institutionalized tyranny.