America is a nation of merchants. Our education system prepares us for a lifetime of trying to sell ideas, people, and proposals to those whose pockets we wish to pick. As a result of this, we know no other way of being, so when it comes time to pick a mate, a religion, a place to live, or a President, the process is exactly the same.
First comes the slimy creature from some shit-based think tank with a handful of greasy bills ready to be traded for favors. Uncle Bubba's dimwit son now has a job polishing the thumbprints off black limos for the district representative. The process was the same as going up to the slimy guy that runs the night shift at the local greasy spoon, and slipping him a couple bucks to put cousin Doofus's idiot daughter to work in the kitchen.
Every worthless endeavor is made more valuable by the appropriate advertising. It starts off nice enough. Cousin Doofus's idiot daughter has something going for her other than an extreme lack of cranial capacity. It turns out her previous job swinging from poles left her with a small but devoted fan base, so she is chosen to make the commercial for the greasy spoon that turns the dining spot into an overnight success.
Meanwhile, Uncle Bubba's dimwit son has now accumulated a warehouse full of secrets from spying on what really goes on inside black limos. Powerful people begin to both fear what he knows about them and they use him to learn what he knows about their competition. He's invited to important parties to gather information and at one of them he meets Cousin Doofus's idiot daughter who is there as the date of the local (married) representative.
Recognizing each other in the way only two predators with little intelligence to go along with their cut-throat survival skills can, they form a life-long partnership based on who they know and who they blow. And as fate and a good amount of greasy bill swapping would have it, they end up running against each other for President.
And lucky us. We get to choose which one we want representing us to the rest of the world.