Kenyan Finance Minister Uhuru Kenyatta resigned on Thursday, days after being indicted by the International Criminal Court for crimes against humanity during violence that followed the disputed election of 2007.
The departure of Kenyatta and civil service head Francis Muthaura, who was also indicted by the ICC on Monday, deprives President Mwai Kibaki of his most trusted lieutenants in the coalition government formed in 2008 to end the bloodshed.
In a sign that Kenyatta's political ambitions remain undimmed, however, party officials said he had formed an alliance with another ICC suspect, William Ruto, to campaign together for the presidency in elections due by March 2013.
The political alliance unites the two men who were on opposite sides during the bloodshed. Both have been charged by The Hague war crimes court with mobilising youths from their respective ethnic groups to kill each other after the poll.
Kenyatta, 50, the son of Kenya's founding father Jomo Kenyatta and the richest man in the country, faced mounting calls for his resignation as finance minister by some cabinet colleagues following the ICC ruling.
While ministers accused of corruption routinely step aside to clear their names, the attorney general had said Kenyatta and Muthaura could stay in office until appeals against the ICC ruling had run their course, which could take up to a year.
This created a storm as the idea that someone accused of murder and rape could stay in office jarred with the precedents set in corruption cases. Two leading national dailies ran editorials on Thursday saying Kenyatta and Muthaura should go.
Whichever way you look at it, the key beacons for Kibaki have fallen down. For Kenyatta, it's a matter of life and death politically speaking. As concerns the charges, they are serious charges and he has to focus on that, Adams Oloo, a university lecturer on political science, said.
The presidency said Robinson Githae, a lawyer and cabinet minister for metropolitan development, was named acting finance minister. Githae told Reuters he would formally address the media on Monday about his new appointment.
There was no immediate reaction on Kenyan markets as the news broke moments before the close. Githae's statements and policies will be watched closely as Kenya, east Africa's largest economy, is battling double-digit inflation, a weak currency, slowing growth and a deteriorating balance of payments position.
Kenyatta has said he is innocent of the charges that he directed an ethnic militia accused of murder and rape during the violence that killed some 1,220 people and uprooted hundreds of thousands after the disputed election.
The presidency said Kenyatta, however, would remain deputy prime minister. The positions of prime minister and two deputies were created in 2008 as part of the deal to end the electoral bloodshed and form a coalition government.
Kenyatta said on Twitter his resolve was unbowed.
As I have already indicated previously, my conscience is clear, my will is strong and my resolve remains undeterred, Kenyatta tweeted. Looking forward to meeting you all as I traverse the country in the coming weeks.
Kenyatta is a member of Kenya's largest tribe and one of the country's most prominent families with extensive land and business holdings and is a close ally of President Kibaki, who is barred by law from running for a third term.
Kenyatta has long wanted to follow in the footsteps of his father Jomo Kenyatta, the first president of Kenya after independence from Britain in 1963, and lead the country as the flag-bearer for the largest ethnic group, the Kikuyu.
While Kenyatta has not commented on his presidential ambitions following the ICC ruling, he said a day before the decision that it would not affect his plans to stand.
Party officials told Reuters he is due to make his first public appearance at a political rally with Ruto on Friday in Eldoret, a key town in the Rift Valley in Ruto's political powerbase, near the epicentre of the post-election violence.
We are looking at the bigger picture, this is competitive politics and we need to come together to win, said close Kenyatta ally and legislator Lewis Nguyai, who testified for the finance minister at the ICC.
Ruto, from the Kenya's third largest ethnic group, the Kalenjin, has insisted he will still run for president despite the ICC charges and plans to appeal against them as a first step to avoid going to trial.
But there are already legal challenges by rights groups to stop Kenyatta and Ruto running for president.
We have been forced into a corner, to be condemned together and the only way out is to join forces, Charles Keter, a legislator, and close Ruto ally told Reuters.
Politics is a game of numbers. If we team up, we will win, he said, adding the two had not yet formally settled for a single candidate, and the two leaders' respective parties had yet to strike a formula on how to run a joint campaign.
Some analysts said while a Kikuyu-Kalenjin alliance would be a very strong contender, and may reconcile the two communities after the election violence, it could also backfire.
If they stay together in a unity of the accused, they could been seen as standing for impunity and face a voter backlash, political commentator David Makali said.
(Editing by David Clarke)