OPINION: Morocco and its AU ambitions
It was such a bad tempered and bitter departure 32 years ago that it is hardly surprising the return, if it happens at all, will be messy.
Morocco surprised many at the African Union summit in Kigali earlier this month, saying it wanted to join the African Union (AU).
The host, President Paul Kagame, was not among those taken aback.
He received Morocco's King Mohammed VI as an honoured guest in his capital earlier this year and conferred Rwanda's high civic honour on the man known as M6.
Neither, presumably, did Morocco's intention come out of the blue for the 28 African states that have supported the kingdom becoming a member of the AU.
Senegal is foremost among these.
President Macky Sall refers euphemistically to Morocco's "independence tussle" with Western Sahara.
He spells out that the kingdom wants the African-Union-recognised Saharawi Arab Democratic Republic (SADR) suspended from the African Union before it is admitted.
African powers like Algeria and South Africa find such a notion absolutely preposterous.
They take the conventional view that Morocco invaded the Western Sahara in 1976 and has been in illegal occupation of the country ever since.
The recognition of the SADR by the Organization of African Union (OAU) in 1984 caused Morocco to walk out in a high dudgeon.
The kingdom has elected to be the only African country not to be a member of the continental body.
It continued this stance in 2002 when the African Union evolved out of the OAU.
The AU position is that the Western Sahara is the last colonial question in Africa.
So, Morocco has to end its occupation of the SADR if it wants to join the AU.
It would be impossible to come into the African fold as a colonial oppressor.
And it certainly cannot expect to be embraced by the continent at the expense of an established AU member of the SADR.
The United States would like to see Morocco join the AU. It regards this as a "very important" step of a "strategic partner" of the US that would "benefit the whole continent".
However, Washington has steered clear of talking about Morocco's illegal occupation of an AU member.
In a message to the Kigali summit, King Mohammed VI said, "Morocco's friends have long been asking the kingdom to return among them so that Morocco may take its natural place within its institutional family. That time has now come."
The king said Morocco would join the AU without precondition - leaving it to its supporters to specify the desire for the expulsion of a member state.
The United Nation's Secretary General Ban Ki Moon refers to Morocco's presence in the Western Sahara as an occupation.
Saharawis have been driven into refugee camps in Algeria, resulting in a humanitarian crisis.
So angered was Morocco by the Secretary General's language that it expelled UN peacekeepers from areas of the occupied country under its control.
The action was denounced by the African Union for setting a "dangerous precedent" and threatening regional peace with recklessness and disregard for the Sahrawi people's right to self-determination,
The AU expects an apology from Morocco, adding that Morocco's membership of the AU cannot come without pre-conditions.
At the very least, Morocco would have to keep its promise made when a delicate peace was brokered with the Saharawi guerrillas known as the Polisario Front in 1991 to have a referendum in the SADR.
The Saharawi accept there may be a case to be made that no-one has a right to deny Morocco a seat in the African Union.
However, it is adamant that no-one has a right to deny the SADR its sovereignty if that is what its people desire.
"Modern Africa cannot pretend to be blind to modern colonialism, violent and vile in nature. This situation should be fixed. Welcome back Morocco, but there is a lot of work to be done."
Jean-Jacques Cornish is an Africa correspondent at Eyewitness News . Follow him on Twitter: @jjcornish