Mr. Odinga, who is now prime minister, had accused President Kibaki of rigging the presidential ballot to win a second term in office. Allegations of election fraud were followed by widespread violence that claimed more than 1,000 lives and displaced hundreds of thousands of Kenyans. The clashes were fueled by longstanding ethnic resentments and anger over economic disparities.

Mr. Kibaki and Mr. Odinga agreed to form a joint government at the end of February, during crisis talks mediated by former United Nations Secretary-General Kofi Annan.

While it was envisaged that posts would be shared equitably, the Party of National Unity (PNU) has retained control over many key portfolios, notably finance, justice, defense and foreign affairs. This dominance has raised concerns that the Orange Democratic Movement (ODM) may ultimately feel too marginalized to continue within the unity government.

Ministries headed by ODM members include those for local government, public service and agriculture.

“The other side (the PNU) was arrogant, and since they had claimed victory (in the elections), they wanted to cling to powerful ministries to show they were more entitled to power than ODM,” author and political analyst Peter Ombui said. “But Odinga salvaged the country from doom. In that aspect, he is the big winner.”

Deborah Okumu, executive director of the Kenya Women’s Political Caucus, a nongovernmental organization based in the capital of Nairobi, believes that the ODM still has the chance to make a mark in government.

“I don’t think Odinga lost out, although that is the perception among his supporters. If his people take up their ministerial roles with gusto, they will transform their ministries and make them as powerful as any other,” she said. “I have been a civil servant and I know a ministry is as powerful as the minister.”

Nonetheless, Kenyans remember all too clearly that an earlier government which brought together Mr. Kibaki and Mr. Odinga failed.

Before the 2002 polls, Mr. Odinga threw his support behind Mr. Kibaki’s National Rainbow Coalition, reportedly in exchange for a pledge that he would be made prime minister. By 2005, however, this arrangement had collapsed, with Mr. Odinga leading a campaign to oppose a new constitution that entrenched a powerful presidency.

Then there is the sheer cost of the cabinet, which has 42 ministers. Thanks to the new—and some say overlapping—posts created to accommodate both the PNU and ODM, the cabinet now includes almost half of the Kenyan parliament. What with the salaries of ministers, their deputies and staffers, the allowances given to cabinet members, and the range of perquisites they have access to, the cabinet will be a considerable burden on the public purse—this in a country where close to 23 percent of the population lives on less than $1 a day and almost 60 percent lives on under $2 daily, according to the latest United Nations Human Development Report.

The cabinet that Mr. Kibaki led ahead of December’s ballot had 34 ministers, and former President Daniel arap Moi’s teams had a maximum of 28.

“I know there has been some debate about the size of the government, but what is important is that we do have a government,” said Mr. Annan, who was in Nairobi to witness the swearing-in of ministers.

Over recent weeks, it seemed doubtful at times that a new cabinet would be put in place, as the PNU and ODM were at loggerheads over the allocation of powerful ministries, civil service and other posts. This led, in turn, to fears of a return to widespread violence.

A cabinet was finally agreed upon in mid-April.

“We have been to hell and back. Never again in our history must we return to those times. … We must preserve our dignity and remain united,” Mr. Odinga said April 17, after being sworn in.

The ODM leader is the second person to hold the post of prime minister in Kenya; the country’s first president, Jomo Kenyatta, held the position at independence in 1963 before scrapping it the following year to create the presidency.

Other guests at the ceremony included former President Moi, Ugandan President Yoweri Museveni, Tanzanian Prime Minister Peter Mizengo, Rwandan Prime Minister Bernard Makuza, Burundian Vice President Yves Sahinguvu and former Malawian president Bakili Muluzi.

The immediate priority of the new government is resettling those displaced in electoral violence. Over the longer term, it will need to draft a constitution that devolves power, and it will need to deal with social inequities, notably concerning land ownership.