    *NOTE to the author     there is a big difference between the two parties. Democrats are more liberal and Republicans are a lot more conservative.       Note to the Note   The question was related to the PARTIES, not the philosophy of individual members.
Election manifesto is a vision and misssion of contestent political parties that stand for upcoming election. This is an agenda for future plan made by the political parties wittheir the voters. If any political parties win the election that is bound to implement to the same that was pre-committed with the people.
The formal purpose of such a convention is to select the party's nominee for President, as well as to adopt a statement of party principles and goals known as the platform and adopt the rules for the party's activities, including the presidential nominating process for the next election cycle.