A reason for doing nothing about Mugabe

From Vanity Fair: "The world’s major powers are unlikely to take significant steps against Mugabe. Zimbabwe lacks both of the two exports—oil and international terrorism —that attract direct intervention"

Forget the oil part, but it seems a good thing to send a message to dictators that if you don't cause trouble for other countries we will leave you alone.

Part of the cost to a dictator of engaging in terrorism is:

(The trouble that other nations will cause you if you engage in terrorism) -
(The trouble that other nations cause you if you don't engage in terrorism)

If we tried to remove Mugabe we would be raising the second term and so decrease the price to dictators of engaging in terrorism.