It is time to acknowledge that the international community's strategy on Zimbabwe has failed.

Robert G. Mugabe's regime has survived even as the economy deteriorates further (unemployment is above 70 percent, and gross domestic product will decline another 7 percent this year) and personal freedom suffers greater assaults (the recent "drive out the rubbish" campaign left 700,000 people homeless).

Indeed, with the opposition Movement for Democratic Change (MDC) on the verge of collapse - following a bitter fight over whether to boycott the recent Senate elections and after years of sustained government pressure - the regime has a stronger grasp on power than ever. Doddering though he may be, Mr. Mugabe, who recently turned 82, has foiled the pressure of the United States and Britain and the quiet diplomacy of his neighbors in southern Africa.

Predictions of imminent change still crop up in Western newspapers on the occasion of every new crisis in Zimbabwe. But these predictions have not come to bear, and they likely will not. So long as Mr. Mugabe reigns, his Zimbabwe African National Union-Patriotic Front (ZANU-PF) regime will survive.

The international community tried to change things. It embarked on a strategy of concerted economic and diplomatic pressure to weaken the Mugabe regime, trying to force it to either back down or submit to the democratic opposition. It's clear that strategy has failed.

It is, therefore, time to focus international attention on the prospect of Zimbabwe's only genuine political opening in the years ahead: the exit of Mr. Mugabe, whether through retirement or death, which will leave the regime internally and externally vulnerable.

Internally, the ZANU-PF regime without Mr. Mugabe at the helm will be uniquely susceptible in an election. In sub-Saharan Africa, opposition candidates have won post-transitional elections only 5 percent of the time against incumbents but 33 percent of the time against regimes' designated successors.

The most important reason for that is the incumbent's exit removes the regime's glue. The regime fractures into competing factions and is left with a substantially reduced capacity to repress the political opposition and rig an election.

In Kenya, after President Daniel T. arap Moi, and in Ghana, after President Jerry J. Rawlings, the regimes did not - could not - resort to all the dirty tactics that they certainly would have used had the incumbents run. In turn, these political openings have tended to galvanize the fractured opposition to successfully cooperate.

A ZANU-PF that is deeply unpopular, badly fractured among ethnic groups and between moderates and hard-liners (the expulsion of the information minister, Jonathan Moyo, is the beginning) and facing a reinvigorated opposition will not likely be able to effectively rig elections, let alone win the popular vote.

It will be critical, then, that presidential elections be held within a year of Mr. Mugabe's exit, before the regime has too much time to consolidate. If Mr. Mugabe's exit does not occur within that window before the 2008 elections, then international, and particularly regional, pressure will be crucial in forcing early elections.

Externally, Mr. Mugabe's exit may prompt genuine regional pressure. Analysts have long emphasized that international pressure requires the support of Zimbabwe's neighbors - especially South Africa - that have significant political and economic leverage. But to the great frustration of Western governments, southern African countries have thus far refused to publicly challenge Mr. Mugabe.

Their reluctance has much to do with Mr. Mugabe's status as a hero of Zimbabwe's anti-colonial struggle and a champion of liberation struggles elsewhere. Southern African nations will have much greater political room to apply real pressure on Zimbabwe when its leader lacks such credentials.

Simultaneously, the prospect of an altogether different level of violence might shake the complacency of southern African nations. Zimbabwe's implosion has not, thus far, been entirely bad for its neighbors. They have benefited from the elimination of economic competition and from the influx of professionals, and they have retained confidence that Mr. Mugabe can keep control.

But there is a real danger, if a post-Mugabe Zimbabwe is not handled adroitly, that elements of the opposition, disaffected war veterans and youth militia and losers in the ZANU-PF factional battle will take up arms and plunge Zimbabwe into civil war.

This specter should push neighboring countries to step up their efforts, especially to press the post-Mugabe regime to hold new presidential elections and encourage moderate elements within ZANU-PF.

Notwithstanding its occasional fulminations against Zimbabwe, the United States has failed in its efforts to unseat Mr. Mugabe's regime. The United States should focus now on his eventual exit by helping the MDC to overcome its bitter infighting and engaging Zimbabwe's neighbors, especially South Africa, in vigorous diplomacy, pushing them to prepare for the occasion.

The stakes could not be higher, for if the post-Mugabe period is the first genuine opportunity for political change in Zimbabwe, it may also be the last for some time.