In a fair democracy everyone’s vote should count equally, but the method that the United States uses to elect its president, called the electoral college, violates this principle by making sure that some people’s votes are more equal than others.  The Electoral College is, essentially, the 538 votes that determine who wins the presidency.
If these votes were split evenly across the population every 574,000 people would be represented by one vote.  But that’s not what happens because the Electoral College doesn’t give votes to people, only states. Which has some unfair consequences.
For example there are 11,500,000 people in Ohio so, to fairly represent them, it should get 20 electoral votes. But the Electoral college doesn’t give Ohio 20 votes, it only gets 18 – two less than it should.
Where’d those other votes go? To states like Rhode Island.
Plucky Rhode Island has 1.1 million people in it, so it should have about two votes, but instead it gets four.  Those extra two votes that should be representing Ohioans go to representing Rhode Islanders instead? Why?  Because, according to the rules of the electoral college, every state, no matter how few people live there, gets three votes to start with before the rest are distributed according to population