Mugabe gave him an implicit ultimatum:

Give up or I'll kill your supporters.

If Tsvangirai was the egomaniac that Mugabe is he might have carried on with his Glorious campaign.

But the difference between them is that Tsvangirai doesn't see other peoples lives as currency with which to make political gambles.

He had to withdraw.

The people have no food, let alone the resources to support any kind of uprising.

Mugabe has crushed them underfoot as revenge for embarrassing him at the last election.

Tsvagirai is right, it is a war between Mugabe and the Zimbabwean people, waged with economic sanctions and violence.

Mbeki is a spineless toad.