Backer's Vote is a term used in politics to refer to a vote of support from someone who has a vested interest in the outcome. It is usually given by someone who has a financial stake in the result, such as a donor or investor. The term 'YEA' is a three-letter word that is used to signify a vote in favor of a particular proposal. In this context, it is used to indicate a vote of support from a backer.