LAGOS (Reuters) — Confidence in Nigeria’s elections is ebbing on signs President Olusegun Obasanjo is manipulating the process to install a puppet, Western diplomats said this week.Africa’s top oil producing nation has witnessed its longest run of democracy under Obasanjo, and the April poll should mark the first transfer of power from one elected leader to another in its 47 years of independence.

Obasanjo has promised a free and fair vote, but diplomats say the former army ruler is abusing powers of incumbency to disqualify opposition candidates, hinder preparations and brow-beat the ruling party into backing an unknown candidate.

“As Obasanjo enters the final months of his second four-year term, he is subverting his country’s fragile democracy in order to prolong his personal power,” wrote Herman Cohen, a former US assistant secretary of state for Africa, in the International Herald Tribune newspaper last week.

Cohen’s views are shared by some senior Western diplomats in Abuja, although they have been careful to limit their public statements to expressing support for a free vote and emphasising the importance of the May 29 handover date.

Senior Western diplomats interviewed for this story asked not to be identified. Nigeria’s constitution bars anyone indicted for fraud by an administrative panel of inquiry from standing for president or state governor. Last week the Independent National Electoral Commission (INEC), which the opposition accuses of favouring the ruling party, said it would bar dozens of mostly opposition candidates on the basis of corruption indictments by a government panel.

The final list of indicted candidates has not been released, but Vice President Atiku Abubakar, who is running for president on an opposition ticket after the ruling party forced him out, has already been indicted by a panel of Obasanjo’s ministers. The anti-fraud police last week started a probe into suspected opposition sympathisers in INEC, amid local media reports that they were against disqualifying Abubakar.

Voter registration has also raised questions about the upcoming election’s legitimacy. The process has been hindered by a massive shortage of registration machines, and many in the opposition have accused Obasanjo of being responsible.

“It’s getting worse and worse,” a senior Western diplomat said, asking not to be named because he said he could be thrown out of the country for speaking out. “They manipulate the voter list, the candidate list and the people in charge of elections. At what point do we say this is a fraud?”

Nigeria is the world’s eighth largest oil exporter and diplomats say a credible poll in April would go some way to reducing the widespread disillusionment with government which fuels violence, particularly in the oil producing Niger Delta where militant attacks have cut output.

A president without a popular mandate could plunge Africa’s most populous nation further into chaos, they say. Support for the ruling People’s Democratic Party’s (PDP) candidate, Katsina State Governor Umaru Yar’Adua, is based almost entirely on Obasanjo.

The retired general corralled party delegates into voting for Yar’Adua at December’s primary with threats of fraud probes, insiders say. Obasanjo, 69, then forced through new rules to make himself life chairman of the party after he steps down, with control over policy, membership and finances.

Because of the lukewarm support for Yar’Adua, diplomats say the PDP is likely to engage in vote rigging. It was accused of rigging the 2003 poll, when Obasanjo won a second term.

Critics say Obasanjo wants to disqualify Abubakar because he fears PDP kingmakers, enraged by his tactics at the primaries, could spring a surprise on him at polling day and vote for Abubakar, who is popular with many of the 36 state governors.