affected the value of their vote in a constituencies and districts. Both the rolls voted for each type of seat. For the constituencies, if the B roll total exceeded one-fifth of the total votes, it was devalued to a maximum of one-fifth. In practice, this never happened, due to the African nationalist campaign to boycott elections. For the districts, if the A roll total exceeded one-fifth of the total votes, it was devalued to a maximum of one-fifth. This was always the case. 1970 constitution In the 1970 constitution, the electoral system was changed with the 'B' roll being abolished. Instead, the electorate were segregated by race with European, Asian and mixed citizens meeting certain income and property qualifications – an annual income of 1,800 dollars or more for the past two years or immovable property worth 3,600 dollars or more, with either demand lowered by a third if the person had completed four years of secondary education – voting in 50 constituencies, with Africans meeting lower qualifications – an annual income of 600 dollars or more for the two past years or immovable property worth 1,200 dollars or more, with either demand lowered by a third if the voter had completed two years of secondary education – voting in eight. In addition, there were eight seats elected by an electoral college of African tribal chiefs. Prime Minister Ian Smith justified this setup on the grounds that the vast majority of black Rhodesians had no experience with the democratic system. White Rhodesians feared that rapid transition to majority rule might yield similar hardships to those experienced by the other newly independent African states such as Ghana, Tanzania, Uganda, and Nigeria. Smith proposed a gradual inclusion of Africans, increasing as the African population got to understand the system. This was based on the contributions to the fisc, hence the 50–16 split in the 66-seat chamber, with a new Rhodesian Senate being instated as well. Critics counter that this was simply a strategy to perpetuate European settler rule for as long as possible, and whether this transition would have happened over the next few decades is unclear. Elected governments From 1924 to 1933, the Rhodesia Party (a renaming of the 'Responsible Government Association' which had campaigned for the grant of autonomy) dominated the government. In 1933, the Reform Party, a modestly progressive group, won the election, but within a year the more