U.N. Deputy Secretary-General Asha Rose Migiro called this a "moment of truth" for Africa's leaders. But if it was, the truth was unpleasant.
In an address to a pre-summit session, Migiro, a former Tanzanian foreign minister, described the failure of democracy in Zimbabwe as the single greatest challenge to stability in southern Africa.
On the summit sidelines, America's top diplomat for Africa Jendayi Frazier described Robert Mugabe's claim to a sixth term as Zimbabwe's president "an open expression of tyranny." She said the world would be watching to see how Africa's leaders would respond.
The British Minister Mark Malloch Brown bluntly told reporters "Mr. Mugabe has to go."
But these expressions of international outrage seemed not to matter. When Mr. Mugabe arrived at the summit hall, he was warmly greeted by the host, Egyptian President Hosni Mubarak, whose 27 years in office is one less than Mr. Mugabe's 28.
Africa's longest serving head of state at 41 years in office, Gabon's Omar Bongo hailed his Zimbabwean colleague as a hero.Muammar Gaddafi, whose 39 years in office makes him second in seniority among Africa's leaders, was also there to join the welcome.
It only underscored the point that a fair percentage of Africa's heads of state are strongmen who, one way or another, have installed themselves as leaders for life.
And Mr. Mugabe, through his spokesman George Charamba, made clear to reporters that he couldn't care less what the West thinks of his election.
"They can go and hang. They can go and hang a thousand times. They've no claim on Zimbabwe at all, and that's exactly the issue," he said.
Charamba described Zimbabwe's presidential vote as an internal affair, and none of the outside world's business.
"The way out is the way defined by the Zimbabwe people free from outside interference, and that is exactly what will resolve the matter," he added.
And Africa's leaders, by and large, seemed to agree. After what was described as a heated closed door debate, the leaders issued a mild statement with no rebuke.
Diplomats attending the session say Nigeria's President Umaru Yar'Adua confronted Mr. Mugabe over the conduct of his election, but that the Zimbabwean leader replied that Nigeria's election was even dirtier.
Political analyst Medhane Tadesse of Addis Ababa's Center for Policy Research and Dialogue says that kind of criticism resonates with many African leaders.
"Most of the leaders in Africa look at Zimbabwe like in a mirror their own face, which means they are not prepared to seriously pressurize Zimbabwe and President Mugabe," he explained."So on the one hand you have the advancement of democratic principles. On the other hand the interest and survival instinct of political leaders doesn't cope with those advanced principles. I see that contradiction."
Medhane concludes that Africa's authoritarian rulers will not change their anti-democratic ways unless the international community steps in and forces them to do so.
"There is not an international mechanism to enforce democratic elections, which means every aspect and mechanism of change in Africa, and political transition is being shut down," he added."So there needs to be an international mechanism to enforce democratic elections and democratic election should be rewarded while undemocratic elections should pay the consequences. Unless that is done, there is not much Africa can do."
In the meantime, Africa's optimists point to a ray of hope. Word from inside the summit hall was that a small, but vocal minority of African leaders joined the international chorus of outrage at Mr. Mugabe's assault on democracy.
The vice-president of neighboring Botswana, Mompati Merafhe told the gathering Zimbabwe's election does not confer legitimacy on Mr. Mugabe. He urged Zimbabwe's suspension from the African Union and the regional grouping of southern African nations (SADC).
The leaders of Nigeria, Liberia, Sierra Leone, Guinea Bissau, Senegal and Uganda also expressed support for action against the Mugabe government.
Zambia's President Levy Mwanawasa had been expected to be a strong voice favoring a censure of Mr. Mugabe, but he was struck down by a stroke shortly after arriving at the summit site, and did not attend.
Western diplomatic observers point to those dissenting voices as a silver lining to the cloud hanging over the African Union. As one quipped, "If eight of Africa's 53 heads of state criticized the conduct of the election, that's a positive trend."