Apartheid was a system of racial segregation in South Africa enforced through legislation by the National Party, the ruling party from 1948 to 1994. Under apartheid, the rights, associations, and movements of the majority black inhabitants and other ethnic groups were curtailed, and white minority rule was maintained. Non-white South Africans were forced out of their homes into segregated neighbourhoods, were deprived of their citizenship and political representation. As could be expected, apartheid sparked significant internal resistance, violence, and a long arms and trade embargo by the global community.
Racial segregation had existed in South Africa since colonial times under both the Dutch and British but it was not until 1948 that apartheid existed as an officially structured policy. Rising tensions between white and non-white communities gave rise to the National Party, standing on a policy of apartheid with a set of draconian rules designed to assert white dominance. However, a majority of white South Africans did not vote for the National Party in 1948. In fact, only 37% voted for their vision of a divided South African society. Despite receiving fewer votes than the United Party, the National Party won most of the seats because of the distorting effect of the First Past the Post (FPTP) voting system.
South Africa's broken voting system (the same one we still use in the UK) gave them a government that did not have majority support and ultimately gave them a racist system of oppression that lasted for over 40 years.
Over the next 10 general elections in South Africa, the pro-apartheid National Party won a majority every single time, sometimes with upwards of 80% of the seats, despite receiving less than 50% three times and never getting more than 65% of the vote. Their dominance in parliament allowed them to entrench apartheid segregation and consolidate power.
FPTP means that elections are decided by a small minority of voters, sometimes with disastrous results. Because parties can achieve a majority of the seats with a minority of the votes, there is no check on their power and they are free to rule entirely as they please, rather than in the interests of the majority. FPTP distorts the will of the people and hands political power to a small minority of swing voters in marginal constituencies.
In the 1990s, partly due to international pressure and partly due to internal violence, apartheid became untenable and reforms began to be negotiated to bring it to an end. Non-white South Africans were given the vote, First Past the Post was replaced with Proportional Representation and in 1994, South Africa had its first free elections. Nelson Mandela's African National Congress won 63% of the votes and thus 63% of the seats.
If South Africa had a proportional voting system in 1948, the National Party would not have won the election and instigated apartheid. Even if they had won the most votes, under a proportional system they would've been forced to work with other parties and make compromises; this would've helped prevent the hardline racist policies they pursued.
Fortunately, South Africa now has universal suffrage and proportional representation. In the UK, we are blessed to have had universal suffrage for almost 100 years, but we are still burdened with our archaic FPTP voting system. To avoid the concentration of political power in the hands of a small number of voters in a small number of marginal seats, we need a voting system where every vote counts equally and everyone has a fair voice. We need proportional representation.