What are the principal reasons for the persistence of the two party system in america?

There are several reasons why the two party system persists in America. They are as followed:

1) Strong history of success- All of the US Presidents in the last roughly 100 years have been part of either the Democratic or Republican Party. There has not been a third party candidate who has been able to win the presidency in over a century. So, if a person wants to be president, they have to align themselves with either the Democratic or Republican party.

2) Funding- It is extremely difficult for third parties to compete with the amount of money the Republican and Democratic parties can raise. Annually, these organizations raise hundreds of million dollars through private donations.

3) Little incentive to form another party- Since most elections are winner take all (aka only one person gets the position), there is very little incentive to form another party where the individual is bound to lose.

The answer would be advertising.