"Mugabe is almost a throwback to a 1970's archetypal African dictator," says Calingaert. "Leaders of other African countries want the rest of the world to know that they are forward looking. Zimbabwe is a humanitarian crisis. On that basis, countries that might not have a perfect electoral record should feel very justified in intervening," he says.
Opposition leader Morgan Tsvangirai withdrew from the race this week, citing the Mugabe regime's "campaign of violence" against his supporters. At least 86 people have been killed and more than 200,000 displaced since the initial presidential election in March, which Tsvangirai won narrowly.
Both the diplomatic community and human rights groups want the SADC and the AU to put pressure on Mugabe to allow a fair vote to take place.
And there are African countries who Gagnon says are "stepping up to the plate" and pushing for a transitional governing body to lead Zimbabwe until the political situation can be stabilized enough to conduct free and fair elections. Tanzanian President, and AU chairman Jakaya Kikwete has been vocal in his criticism of President Mugabe, and so has Jacob Zuma, the head of South Africa's powerful ANC party.
But criticism alone is not enough. "They need to say that they're not going to recognize Friday's presidential election results," says Gagnon. "We haven't heard that yet."