ZIMBABWE'S prime minister, Morgan Tsvangirai, can be forgiven for being an angry man. Not only has Robert Mugabe failed to implement the agreement that created Zimbabwe's unity government between Mugabe's Zanu PF and Tsvangirai's MDC, the cables unleashed on WikiLeaks in recent days have revealed just what one of his key allies thinks of the prime minister.

The country is abuzz with details of what America's former ambassador to Zimbabwe thinks of Tsvangirai. It is of course the view of one man, Christopher Dell, but to many, the US has spoken. As Thursday's Guardian editorial put it: "The cables were written by Americans, to be read by Americans and they form the undigested raw material of American policy."

And what the US had to say about Tsvangirai is so raw as to be downright unflattering. Tsvangirai, according to Dell, is "a flawed figure, not readily open to advice, indecisive and with questionable judgment". He is, Dell wrote, "an indispensable element for opposition success … but possibly an albatross around their necks once in power. In short … Zimbabwe needs him, but should not rely on his executive abilities to lead the country's recovery."

The Guardian pointed out that many of the diplomats' cables are "are consistently well-informed, well-sourced and well-judged". Tsvangirai's spokesman issued a bellicose response: Dell's assessment of Tsvangirai, he said, was contrary to the views of the increasing number of Zimbabweans who have been supporting him since 1999.

But this is beside the point. The reality is that Tsvangirai has always been a protest choice, and not a real one. Given the choice between him and Mugabe, most voters would choose, and have chosen him. But this is not to say that he is by any means the best possible leader for Zimbabwe.

Dell's thinking chimes with what many in Tsvangirai's MDC and outside it have been whispering. There is no question at all that Tsvangirai is a brave man, a decent human being, and from all accounts, a likable one. But his actions as MDC leader have also revealed him to be all the things that Dell has said.

Tsvangirai encapsulates the dilemma of the revolution donated from abroad: for the west, he raises the question of what to do about a pro-democracy leader who is not all that he should be, but represents the best alternative to the regime it is fighting.

Dell compared him to Lech Walesa, but he is more like Hamid Karzai. Like the Afghan leader, he is a deeply flawed man whose success is nonetheless essential to the interests of the US and its allies, and who, flawed as he is, still offers a better alternative to the regime he is fighting.

But the strategy of uncritically supporting the lesser of two evils has been to the detriment of politics in Zimbabwe, and indeed, to its democratic development. Tsvangirai may be a lesser evil, but there is still much about him that causes discomfort. Supporting him has led to multiple contradictions and hypocrisies, both for the people of Zimbabwe and the MDC's western allies.

So while Mugabe is castigated for hanging on to power, and refusing to let democratic processes take place both within his party and the country, Tsvangirai, who intends to stay on as MDC president beyond the constitutional limits imposed by his party's constitution, is considered essential to democracy. In effect, undemocratic means are used to advance supposedly democratic outcomes. And in pushing and supporting a man who as patently flawed as Tsvangirai, they may effectively be creating a monster.

Dell also zoomed in on Tsvangirai's apparent aversion to ideas outside his small narrow circle. Rumours abounded that he wanted to sack Tendai Biti, the finance minister who has proved to be one of the leading lights in cabinet, and who, interestingly, was lauded by Dell as one of only two quality leaders in the MDC. This, in the context of the elevation of the patently unqualified Theresa Makone to the high profile home affairs portfolio was a shocking development. A flamboyant businesswoman who started life as a beauty therapist, Makone and her equally wealthy husband are said to control party appointments in a way that many consider damaging to the party.

Dell's reflections are therefore an important trigger for a discussion of Tsvangirai and his style of leadership. The MDC has largely escaped scrutiny, as, for that matter, have other actors opposed to Mugabe.

The thinking behind this lack of scrutiny is that those opposed to Mugabe must be in the right. But Mugabe himself is the best example of a revolutionary motivated by idealism who soon found himself opposed to everything that he had stood for. Dell's cables are thus important to an examination of the MDC.