Walter Frederick `` Fritz '' Mondale ( born January 5 , 1928 ) is an American politician who was the forty-second Vice President of the United States ( 1977 â `` 1981 ) under President Jimmy Carter , a two-term United States Senator from Minnesota , and the Democratic Party nominee for president in 1984 , which he lost . Walter Frederick `` Fritz '' Mondale ( born January 5 , 1928 ) is an American Democratic Party politician , who served as the 42nd Vice President of the United States ( 1977 â `` 1981 ) , under President Jimmy Carter , and as a United States Senator for Minnesota ( 1964 â `` 1976 ) .