NEARLY 3 million Zambians are expected to go to the polls today in a ballot that marks a turning point in the country's history and could bolster the trend toward greater democracy in Africa.In the first multiparty elections in 17 years, which follow two years of pro-democracy activity, voters will be asked to choose a president and 150 candidates for the National Assembly. President Kenneth Kaunda, who has led the country since it won independence from Britain 27 years ago, faces a daunting challenge from trade unionist Frederick Chiluba who heads the broad coalition Movement for Multiparty Democracy (MMD). The election campaign so far has been peaceful despite predictions of violence. Western diplomats fear that violence could follow if the MMD fails to win both polls. Dr. Kaunda has warned that an MMD victory could lead to civil war. "Zambia will never be the same again after these elections. Even if UNIP wins, changes will come," says Robinson Mwan, a Zambian businessman in Johannesburg who has returned to vote for the MMD. "The MMD is not a political party. It's a feeling of the Zambian people that can't be stopped." The MMD - made up of trade unionists, businessmen, farmers, professionals, and church people - shares one objective: to remove Kaunda and the United National Independence Party (UNIP) from power and save Zambia from economic ruin. At least 12 smaller parties are also contesting the elections. Once one of Africa's elder statesmen and twice a chairman of the Organization of African Unity, the tide of history has turned against Kaunda. His humanist inclinations cannot conceal the legacy of one-party rule and the devastation wrought by socialist policies on a once prosperous nation of 7.5-million people. Food production has fallen to a fraction of its potential. Hospitals are short of medicines. Schools are without desks and chairs, and national roads are in disrepair. The main airport is dilapidated, and half-empty supermarket shelves gather dust in this once thriving capital. The country is wracked with AIDS, and one of Kaunda's sons died of the disease several years ago. A second son was recently sentenced to death for murder. Soon after Zambia won independence, Kaunda suspended the Constitution and established permanent emergency rule. He nationalized industries - including the copper mines, which account for 90 percent of the country's foreign earnings. After being left with more than $3 billion in foreign reserves when the British withdrew in 1964, Zambia today owes $8 million to international donors - making it one of the highest per capita debts in the world. The World Bank recently cancelled a $260 million loan after Zambia defaulted on a $20.8 million payment. An economic reform plan - backed by the IMF and the World Bank - aims to boost exports other than copper, reduce inflation and the budget deficit, and privatize unprofitable state-run businesses. By December last year, Kaunda was able to read the signs of the growing pro-democracy movement and agreed to abandon one-party rule. In July this year, he agreed on a democratic Constitution and multiparty elections. Most political scientists predict that both he and UNIP will be defeated in the election.