The OECD Anti-Bribery Convention (the unwieldy official name of which is the “OECD Convention on Combating Bribery of Foreign Public Officials in International Business Transactions”) has proven to be a surprisingly successful international agreement—far more effective than the various regional anticorruption instruments or the U.N. Convention Against Corruption (UNCAC), and indeed far more effective than even the OECD Convention’s proponents had predicted. Of course, it’s hard to know how much one can credit the OECD Convention for changes in anticorruption laws and enforcement patterns, but lots of well-informed people believe it has had a big effect, primarily because of its rigorous peer review system. In contrast to other, weaker review systems associated with UNCAC and some of the regional conventions, members of the OECD Convention must submit to a quite extensive and intrusive form of peer review, in successive phases, and cannot veto or prevent disclosure of the resulting reports. The reports are often quite harsh, even scathing, and the political embarrassment associated with a bad review can shame governments and mobilize public opinion.

Given that the OECD Convention has been so successful, should it be expanded to include more countries? After all, membership in the Convention is not limited to the OECD , and indeed several non-OECD countries (Argentina, Brazil, Bulgaria, Columbia, Russia, and South Africa) are already parties. The OECD’s leadership seems to think the answer is a clear yes. At a recent Chatham House conference on “Combating Global Corruption” (which I was fortunate enough to attend), Ángel Gurría, the OECD Secretary-General, declared that it was “imperative that all G20 countries become Parties to the OECD Anti-Bribery convention,” and specifically noted the importance of bringing China, India, Indonesia, and Saudi Arabia on board.

I’m sympathetic to the general idea, and would certainly like to live in a world where all countries accepted—and respected—the commitments embodied in the OECD Convention. But rapid expansion of the Convention has important drawbacks that deserve more attention than they seem to be getting. So at the risk of being the skunk at the garden party, let me lay out the case for skepticism about rapid expansion of the OECD Anti-Bribery Convention.

The skeptical argument is actually pretty easy to summarize: rapidly expanding the membership of the OECD Convention risks weakening the Convention. At a time when over half of the current Convention members have not yet successfully prosecuted a single foreign bribery case, this is a substantial concern. The OECD Convention only works because the peer review system is effective. But the peer review system is only effective because (1) countries are willing to issue harsh reports about their peers, and (2) countries care about the reports, and find bad reviews embarrassing and/or politically damaging. The rapid addition of new members—particularly those that are less than fully committed to combating bribery of foreign public officials—risks eroding each of these two bases of the Convention’s effectiveness. Consider each in turn:

As to the first: It’s true that under the OECD Convention, no one country can block a report—the system works not by consensus, but by “consensus minus one.” Yet the more countries that are part of the system—and the more of those countries that have a less-than-stellar record on anticorruption—the greater the worry that the peer review system will be watered down. Explicit, secret collusion is not unthinkable—if French and Russian figure skating judges would collude to favor the other nation’s Olympic competitors, it’s not outside the realm of possibility that French and Russian officials would agree to go easy on one another when assessing the vigor of anticorruption enforcement. But the more plausible concern is that participants in the peer review process might assess another country’s behavior through the lens of what is “normal” or “acceptable” in their own countries. Additionally, insofar as the rigor of some Convention reports is driven by a handful of countries with a strong interest in this issue (such as the United States, Germany, and perhaps now the United Kingdom), a larger pool of potential reviewers means that there’s a lower likelihood that representatives from one of those jurisdictions will be in the set of primary reviewers for the initial investigation, and the less influential those countries might be in the negotiations over the final language in the reports.

As to the second factor: Currently, a bad report is embarrassing because countries—or active and influential citizens within those countries—care what the OECD Convention members say about them. There’s a sense that all these countries are part of the same “club,” and this is what makes shaming an effective motivator. But that tool may not be nearly as effective against countries that, for better or worse, care less about what the “club” thinks about them on this particular issue. China and Saudi Arabia, for example, get criticized for their human rights record all the time, and it doesn’t seem to make much difference. And the more OECD Peer Review Reports are ignored or dismissed, the less significant they become. We can flip this around as well: the UK or France or Canada may care quite a bit when they are raked over the coals by their fellow OECD countries; will the criticisms have the same sting when they’re coming from a group that includes Russia, China, Saudi Arabia, and Indonesia? Again to use human rights as a comparison, there’s a plausible argument that the moral force of reports issued by the U.N. Human Rights Council is substantially weakened, rather than strengthened, by a membership that includes (or has included) China, Zimbabwe, Russia, Saudi Arabia, Pakistan, Sudan, and Vietnam.

I want to be careful not to overstate my concerns. There are clear advantages to expanding the OECD Convention.  The addition of other G20 countries will not cause the Convention to collapse. And even if expansion does lead to some dilution of some reports, that might be a price worth paying to get major players like China and India on board. But as Secretary-General Gurría acknowledged during his Chatham House remarks, the fact that so many of the Convention’s existing members seem not to be meeting their Convention obligations weakens the Convention, and threatens to undermine its continued effectiveness. In light of that fact, a push for rapid expansion may be premature.  Perhaps expansion of the OECD Convention should remain a long-term goal, but that expansion should proceed more carefully and deliberately. It might make sense to first make sure that the OECD Convention can succeed in getting get France and Finland to vigorously enforce their foreign anti-bribery laws, before trying to bring in China and Saudi Arabia.