"I am a freeman, an American, a United States Senator, and a Democrat, in that order"

Lyndon B. Johnson is specifying that his identity and worths are focused on in the following order: as a freeman, a specific with personal freedom and dignity; as an American, with commitment and dedication to his nation; as a United States Senator, with an obligation to serve and represent his constituents; and as a Democrat, with political affiliations and beliefs.