The political and economic situation in Zimbabwe is spiraling out of control, but the government of the Zimbabwe African National Union — Patriotic Front seems determined to hold onto power no matter what the cost. The time is ripe to impose an arms embargo on President Mugabe’s murderous regime. In order for the embargo to work, however, more pressure will need to be applied on Southern African states in general and South Africa in particular.

The bleak news out of Zimbabwe is getting worse every day. The government has unleashed the army and police against the opposition Movement for Democratic Change. Scores of MDC activists have been killed, tortured, or assaulted. The government’s control of the press and ban on public gatherings made it impossible for the MDC’s candidate, Morgan Tsvangirai, to win the second round of the presidential election. As a consequence, he withdrew from the contest yesterday.

On the economic front, the situation is dire. The economic crisis that was precipitated by Mr. Mugabe’s seizure of commercial farms in 2000 has put four out of five Zimbabweans out of work. The government’s tax revenue collapsed as did most of the public services. The Reserve Bank of Zimbabwe was ordered to print money to make up for the budget shortfall, leading to the first hyperinflation of the 21st century.

By the end of June, the annualized inflation rate will reach 3,140,335%. That will bring the overall inflation for the entire duration of the Zimbabwean hyperinflation to a staggering 366,386,083,683%. That is roughly 36 times the overall inflation experienced by the Weimar Republic in the early 1920s. One American dollar, which bought 50 Zimbabwean cents when Mr. Mugabe assumed power in 1980, sold for 25 billion Zimbabwean dollars on June 9.

Most Zimbabweans, especially those living in rural areas, survive on remittances from their relatives abroad and food aid distributed by NGOs and Western government agencies. But aid agencies worry that with the coming of winter hunger will spread. The ruling regime, however, uses food shortages as a political weapon against the supporters of the opposition — it hands out food to people with the ZANU-PF membership card only.

In the early 2000s, Western nations imposed targeted sanctions against Zimbabwe’s top government officials. The time is ripe to ban the army and police from acquiring the weapons they need to put down internal dissent. An arms embargo has not been contemplated seriously before, because of doubts over its successful implementation.

A successful arms embargo must have the support of Southern African states in general and South Africa in particular. The cooperation of Southern African states now looks more likely. Regional leaders, like those of Angola and Zambia, who have been largely silent about the crisis in Zimbabwe previously, have been increasingly vocal in their criticism of Mr. Mugabe.

They and other African leaders may be open to arms embargo — especially if South Africa changes its policy of supporting Mr. Mugabe. As was the case in the 1970s, South Africa holds the key to the resolution of the Zimbabwean crisis. Back then, the apartheid government judged that the costs of helping the white government in Rhodesia were too great. When Pretoria discontinued its active support of the regime in Salisbury, Ian Smith’s government collapsed and was replaced by Bishop Muzorewa.

Similarly, the goal today should be to make Mr. Pretoria’s support for Mr. Mugabe too costly for South Africa. Thabo Mbeki’s government, currently on the U.N. Security Council, should be backed into a corner and forced to vote on the issue of an arms embargo forthwith.

Moreover, South Africans should be informed that their country’s ambition of becoming a member of the U.N. Security Council will remain a pipe dream so long as they go on backing dictators from Burma, Cuba, and Zimbabwe. Lastly, South Africans should be told that a continued controversy over Zimbabwe threatens the success of the FIFA World Cup that South Africa is to host in 2010.

The presidential election was never likely to produce a resolution to the crisis in Zimbabwe. Mr. Mugabe, after all, made it clear that he will not leave power so long as he lives. As such, an increased international pressure on the Zimbabwean government has never been as needed or as likely to succeed as it is today.

Mr. Tupy is a policy analyst at the Cato Institute’s Center for Global Liberty and Prosperity.