Campaigning in Zimbabwe is peaking as voters prepare to go to the polls Saturday to elect a president, national assembly, senate, and local leaders. Correspondent Scott Bobb takes a look at the candidates and some of the issues from our Southern African Bureau in Johannesburg.

Zimbabwean President Robert Mugabe waves with his cap as he leaves a rally in Bulawayo, 23 Mar 2008

Zimbabwe's President Robert Mugabe since he launched his campaign has pulled out all the stops in his bid to remain the only leader Zimbabwe has known since independence 28 years ago.

"This is the start, official start of our march to another victory, electoral victory," said Mugabe. "We certainly are going to win, it is the margin we are trying to build."

Opposing Mr. Mugabe's bid for a sixth presidential term and the uninterrupted dominance of his ZANU-PF party is opposition leader Morgan Tsvangirai, founder of the Movement for Democratic Change, or MDC. The former trade union leader told journalists in Johannesburg recently that Mr. Mugabe's autocratic style has ruined Zimbabwe.

Morgan Tsvangirai addresses a press conference in Harare, 20 Mar 2008

"Mugabe is now not only the president of the country," said Tsvangirai. "He is the institution that has run our country for the last 30 years, and look at the results, unprecedented levels of decay and misrule and repression."

"So he should be accountable. He has been the incumbent for the last thirty years, who else can be blamed for the problem that the country is facing," he added.

Tsvangirai says rigging robbed him of victory in the presidential vote of 2002. He boycotted the parliamentary elections three years ago which led a faction headed by Arthur Mutambara to split from his group.

The presidential campaign this year has been heightened by a third candidate, Simba Makoni. The former finance minister and Mugabe ally was expelled from ZANU-PF when he announced his candidacy after Mr. Mugabe was nominated at a ZANU-PF congress in December.

Simba Makoni addresses supporters at the launch of his presidential campaign in Bulawayo, Zimbabwe,01 Mar 2008

"When we emerged from the extraordinary congress and it was clear that the expectations -- the hope that I and many other party members had had that we would offer both the party and the country new leadership at the highest level -- had been quashed, I then decided it was time to offer myself," said Makoni.

Makoni is backed by Mutambara and reportedly by some important ZANU-PF leaders.

Both contenders are hoping to win because of popular unhappiness over Zimbabwe's economic crisis characterized by hyper-inflation, 80 percent unemployment and shortages of food, fuel and other basic goods.

Denis Kadima heads the Electoral Institute of Southern Africa, which monitors elections and carries out voter education programs in the region. He says there have been some improvements in the atmosphere surrounding the campaign over previous elections.

"We get the impression that the level of violence is lower than it used to be in the past which is a positive thing, but we hope that other aspects which can't come out clearly now will also go in the right direction," said Kadima.

Human Rights Watch researcher for Zimbabwe, Tiseke Kasambala, agrees to a degree.

"Yes, at this stage in the campaign the levels of political violence are significantly lower than in the past and, yes, on paper the electoral laws have improved," said Kasambala. "But in terms of the rest of the conditions on the ground the electoral process is severely flawed and has been subjected to political involvement by the government and by the ruling the party."

Critics say there has been little voter education. Voter registration lists and the demarcation of new voting districts have not been adequately publicized. Finally they note that the government has excluded observers from countries that it considers unfriendly, in Western Europe and the United States.

The director of the Washington-based Africa Action civic group, Gerald LeMelle, says there is considerable support for the opposition.

"I think Zimbabweans want a change of leadership," said LeMelle. "What has happen is that the leadership, Robert Mugabe and the people who surround him have been in there a long time and typical of dictators who have been in there a long time, they have grown corrupt and their interests are simply personal and they are completely comfortable in allowing the country's economy to collapse the way it has."

But a programmer at Africa Action, Briggs Bonda, says that a splintered opposition is giving an advantage to Mr. Mugabe and the ruling party.

"The opposition has not been able to get its act together. If there was a unified platform for all opposition forces arranged against Mugabe that would be the only thing that would have had the capacity to inspire everyone, even people who are non partisan, to feel like there is a common platform and go out and vote," said Bonda.

An unidentified opposition supporter holds a red card with the words 'Mugabe must Go Now,' during a rally in Bulawayo, 08 Mar 2008

And there are fears of rigging, which observers like Kadima hope will be avoided.

"There has been a lot of attention and we are just hoping that the abuses of the past which are acknowledged by everyone will be of less magnitude this time," said Kadima. "But it's still early days."

He notes that more and more countries in Africa are holding fair and transparent elections and hopes Zimbabwe will join them. Opposition leaders are less optimistic but they continue to campaign, hoping at least to win a large number of seats in the assembly and local councils.