The rise of corruption leads me to an inescapable conclusion: While world leaders are proving capable of addressing nuclear terrorism, one of the most difficult issues facing the international community, they still must do more to address such evils as corruption, which holds entire peoples and countries hostage.

Indeed, those who dream of global nuclear disarmament have reason to feel optimistic. This spring alone, the United States and Russia signed a strategic arms reduction treaty and world leaders have taken steps to block nuclear programs in Iran — including a sanctions agreement announced last Tuesday — and North Korea. To reach their Prague agreement, President Obama and Medvedev had to neutralize influential opponents of disarmament in their respective countries. By word and deed, the biggest nuclear powers have shown that weapons of mass destruction are on their way to becoming things of the past.

Yet it is incumbent upon world leaders to address a root cause of new risks of nuclear proliferation: the corruption that has spread across the globe. I remember how, in the 1970s and ’80s, ordinary people feared nuclear war would begin when the frayed nerves of superpower leaders snapped. Today we fear nuclear weapons and technologies falling into the hands of terrorist groups that seek bloodshed for the sake of bloodshed and operate beyond the formal constraints of nation-states.

Civilian and military officials in volatile regions are willing to share nuclear secrets for money, and the practice makes my own country vulnerable. Corruption is turning into a worldwide evil, comparable to epidemics, the yawning gap between rich and poor, and other systemic threats facing humanity.

Russia, no longer ensconced behind an iron curtain, has integrated into the community of nations and the world economy. It is alarming, however, that one of its exports remains corruption, fueled by a host of eager importers, most notably developed countries in the West. Unfortunately, throughout my country corruption has been transformed into a systemic factor that governs many political and economic decisions.

My partners and I, for example, worked for more than a decade to build Yukos into Russia’s most successful and transparent global energy company — only to see it destroyed to satisfy the corrupt appetites of certain government officials who came to power with Vladimir Putin. If the attack against me was prompted by political reasons connected with my support of the opposition, the destruction of Yukos was driven purely by corruption. (It is especially interesting that the theft of Yukos was defended by certain German politicians, while a large Italian company played a central role as purchaser of some of the stolen assets.)

Corruption slows economic growth and fuels political instability. Consider our transportation infrastructure: Russia is a huge country of bad roads. The pathway to a modern economy and a better life should be freshly paved, but corruption is destroying even this simple hope. A mile of expressway costs Russian taxpayers three to four times more than in Europe, largely because of bribes and kickbacks. Even at this high price, poor-quality work guarantees that repairs will be needed, inviting opportunities for even more corruption.

On a wider scale, it is difficult for me to understand, albeit easy to surmise, why shipments of oil to China are effectively being subsidized by the Russian government. And the European gas market may produce more scandalous surprises.

I rejoiced last month when President Medvedev announced initiatives aimed at fighting corruption. The criminal prohibition on bribing foreign officials and other measures are bold steps in the right direction. But moving ahead will not be simple. Many Russian “corruptioneers” are shifting their ill-gotten gains to China, clearly hoping that the Beijing government will ignore international crime under its nose in exchange for support and the advancement of its own interests.

The future depends on how honest and strong foreign leaders will be in slaying the beast of corruption that is fostering the chaos that fuels radical agendas and violence.

Leading countries must fortify their arsenal of economic and regulatory weapons to identify and target offshore companies and banks that operate under the control of corrupt officials. Such a campaign will succeed only if the Group of 20 cooperates and makes battling corruption a higher priority. This is no less important than the continuation of nuclear disarmament. For if the world doesn’t stop global corruption, corruption is going to stop the development of humanity.

Mikhail B. Khodorkovsky, the former chairman of Yukos Oil Co., has been in prison since being arrested in 2003.