who determines who holds the position of speaker of the house
Speaker of the United States House of Representatives The House of Representatives elects the Speaker of the House on the first day of every new Congress and in the event of the death, resignation or removal from the Chair of an incumbent Speaker.[8] The Clerk of the House of Representatives requests nominations: there are normally two, one from each major party (each party having previously met to decide on its nominee). The Clerk then calls the roll of the Representatives, each Representative indicating the surname of the candidate the Representative is supporting. Representatives are not restricted to voting for one of the nominated candidates and may vote for any person, even for someone who is not a member of the House at all. They may also abstain by voting "present".[9]
Seniority in the United States Senate The president pro tempore of the Senate is traditionally the most senior member of the majority party.
My Ántonia
Article One of the United States Constitution Section Two provides for the election of the House of Representatives every second year. Since Representatives are to be "chosen... by the People," State Governors are not allowed to appoint temporary replacements when vacancies occur in a state's delegation to the House of Representatives; instead, the Governor of the state is required by clause 4 to issue a writ of election calling a special election to fill the vacancy.