Johannesbur -Zambia goes to the polls on Tuesday in a tightly contested race to elect a president after a ruling party power struggle following the death of Michael Sata in office last year.The two top contenders are Defence Minister Edgar Lungu, 58, representing the ruling Patriotic Front (PF), and opposition candidate Hakainde Hichilema, 52, of the United Party for National Development (UPND).At stake are the remaining two years of Sata's five-year term in Africa's second biggest copper producer, where new taxes on the metal have become a surprising election issue.Lungu's party introduced the tax in January, while Hichilema has promised to scrap it, pledging a business-friendly Zambia. 'It's a two-horse race'The rivals - Lungu the lawyer and Hichilema the businessman - drew huge crowds at last-minute rallies, with heavy rain failing to deter supporters.But in the absence of opinion polls analysts hedged their bets."It's a two-horse race," said Oliver Saasa, CEO of Premier Consult, a business and economic consultancy firm. "It's quite clear this a very closely run race."On the streets, election-weary Zambians, who voted in scheduled elections that brought Sata to power three years ago and are also due to cast ballots next year, saw the vote swinging either way.Major opposition party "It's 50-50," said taxi driver Emmanuel Mulenga. "It's pointless to vote in a new party. It will want to start afresh. Let's just allow PF to continue with what it started."But corn farmer Trevor Mabonga, 35, was less supportive: "Continuity of what? Lungu has failed to run a law firm and you think he can run a country."Analyst Neo Simutanyi of think-tank Centre for Policy Dialogue said: "We can safely conclude that the opposition will win this election, but I don't think the margin will be very wide."Hichilema's camp is seen to have received a boost from the infighting within another major opposition party, the Movement for Multiparty Democracy (MMD), whose candidate Nevers Mumba is given little chance.Stable economy Lungu's Patriotic Front goes into the vote badly fractured by a bitter power struggle after Sata's death in October, just three years into his five-year term.Two opposing camps - one led by Lungu and another by interim president Guy Scott - nominated rival presidential candidates.After many weeks of mud-slinging, Lungu emerged as the sole candidate - but of a weakened party.Scott, Africa's first white leader in 20 years, cannot stand for the presidency himself as his parents were not born in Zambia.With ideological differences between Zambia's political parties difficult to pin down, voting patterns are often determined by personalities and ethnicity rather than the issues.Despite growth-oriented policies and a stable economy over the past few years, at least 60% of Zambia's population of about 15 million lives below the poverty line, according to World Bank figures.About 5.2 million people are eligible to cast ballots.Whoever is elected will serve out the remaining 19 months of Sata's term.