Over the past decade, as the United States employed increasingly robust sanctions to gradually ratchet up the pressure on Iran to curb its nuclear ambitions, Washington has struggled with the question of how to elicit more cooperation from China, a major buyer of Iranian crude oil and no fan of sanctions, especially unilateral ones. On June 28, the Obama administration granted China an exemption from U.S. sanctions on the Central Bank of Iran (CBI) for significantly reducing its crude-oil purchases from the Islamic Republic. This suggests that one of the biggest carrots Washington can offer to China in exchange for greater support for the U.S. sanctions regimen is expanded opportunities for China’s national oil companies (NOCs) to invest in oil and natural-gas exploration and production in the United States. The greater the stakes that China’s NOCs have in the United States, the thinking goes, the greater the chance they will think twice about doing business in Iran.

The Chinese government responded to the new U.S. sanctions signed into law by President Obama on December 31, 2011, by saying Washington should not expect any cooperation from Beijing. Over the past six months, officials from China’s foreign ministry have repeatedly stated that China’s energy trade with—and investment in—Iran do not violate the various United Nations Security Council resolutions on Iran and that the new U.S. sanctions would not affect China-Iran energy relations.

Despite Beijing’s implication that China would continue to import oil from Iran at 2011 levels (more than 550,000 barrels a day), the main Chinese buyer of Iranian crude oil, Sinopec, responded to the new U.S. sanctions by dramatically cutting its purchases from Iran by 25 percent in the first five months of 2012. At the end of every year, Chinese oil traders negotiate their supply contracts with National Iranian Oil Company (NIOC) for the following year. The commencement of their negotiations in late 2011 coincided with growing support in Washington, especially on Capitol Hill, for ratcheting up the pressure on Iran by subjecting foreign firms that do business with the CBI—the primary clearinghouse for Iranian oil transactions—to U.S. financial sanctions. When China’s oil traders sat down at the negotiating table with their Iranian counterparts, Iran’s increasing international isolation was palpable. Sinopec pushed for lower prices and a longer credit period, while NIOC insisted on higher prices and a shorter credit period. The two companies did not sign a new contract until late March 2012 (with Sinopec reportedly extracting some concessions, which have not been disclosed publicly), causing the plunge in China’s crude oil imports from Iran.

Moreover, Sinopec recently revealed that it turned down offers to buy additional volumes of Iranian crude at discounted prices. After President Obama signed the new sanctions into law, there was some concern in Washington that the Chinese would undermine his tough policy by purchasing at a discount all of the crude that would otherwise have gone to European and Asian buyers in the absence of sanctions. Sinopec, however, had compelling reasons to decline the opportunity to increase its purchases from Iran; the company does not want to jeopardize its chance to expand in the United States, where it already has signed a deal to invest more than $2 billion in shale assets owned by Devon Energy and is looking to buy assets from Chesapeake Energy. The chairman of Sinopec, Fu Chengyu, is acutely aware of how getting on the wrong side of politics in Washington can scuttle a deal; he was the chairman of China National Offshore Oil Corporation (CNOOC) when that company made its ill-fated bid for the U.S. oil company Unocal in 2005.

Sinopec is not the only Chinese oil company with an incentive to choose the U.S. market over the Iranian one. Its domestic peers, CNOOC and China National Petroleum Corporation (CNPC), also find the United States to be an attractive investment destination. First, all three companies are eager to gain shale-gas technology and operational expertise through partnerships with U.S. firms. On paper, China has considerable shale-gas resources. The U.S. Energy Information Administration estimates that China’s technically recoverable shale-gas resources are 50 percent greater than those of the United States. But China’s NOCs lack the technology and operational expertise to develop them. Second, they want to expand reserves and production, and an increasing number of opportunities to do so are now in the United States, thanks to the boom in America’s unconventional oil and natural-gas production. Finally, the turmoil in Middle East and North Africa over the past two years has prompted China’s NOCs to seek less risky operating environments.

Indeed, Sinopec’s domestic peers also are gravitating toward the United States and away from Iran. CNOOC, which has signed contracts committing it to invest $3.4 billion in Chesapeake Energy’s shale-gas assets in the United States, had a $15 billion contract suspended by the Iranians for lack of progress. China National Petroleum Corporation, which similarly had a $4.7 billion contract frozen by the Iranians for its failure to start work, also is looking for opportunities to partner with U.S. companies in shale-gas projects. Moreover, China’s NOCs have not “backfilled” any projects abandoned by European and Japanese oil companies after their home governments implemented tighter unilateral sanctions in 2010.

It isn’t just China’s NOCs that seem to be backing away from Iran in a bid for access to the U.S. market. Consider the announcement made last year by the Chinese telecommunications firm Huawei Technologies that it was planning to scale back its operations in Iran. Although these operations complied with U.S. and European Union laws, there was at least a partial motivation to keep open prospects for doing business in the United States and Europe.

The ability of the United States to secure additional Chinese cooperation may depend in part on the scale of the investments made by China’s NOCs in the United States. The more money these companies pump into the American market, the more likely they are to refrain from doing deals with Iran that might jeopardize those business prospects. Consequently, creating a more welcoming environment for Chinese investments just might have a geopolitical payoff in the form of greater Chinese compliance with Iran sanctions. Moreover, letting China’s NOCs take the lead in complying with—or at least not undercutting—U.S. sanctions on Iran is politically palatable to Beijing. Chinese officials can maintain their public opposition to U.S. sanctions while avoiding increased tensions with Washington over the Iranian nuclear issue. This dual stance is attributable to the business decisions made by China’s NOCs.

Erica S. Downs is a fellow at the John L. Thorton China Center at The Brookings Institution.

Image: Terence Ong