China’s Premier Wen Jiabao returns to his homeland today having concluded an expensive shopping trip across the Middle East. Chinese business leaders, accompanying Mr. Wen, signed (WSJ subscription required) deals with Arab companies worth billions of dollars, but one of the more interesting details of the trip is the Persian Gulf storefront Mr. Wen and his delegation did not shop at: Iran.None of this is to say that China is about to jump on the Iran sanctions bandwagon. Just last week, in fact, Chinese officials refused American requests to reduce oil imports from Iran. Yet as Wen’s trip suggests, China is moving on its own to diversify its energy supplies. Publicly, Beijing has to take a strong line against American meddling; privately, it recognizes the benefits of reducing dependence on Iranian oil and on dangerous transit routes like the Straits of Hormuz and Malacca. (China is working on pipeline projects aimed at bypassing both those strategic choke points.)China still buys a lot of oil from Iran and will continue to do so. But Beijing’s energy diversification effort is Tehran’s loss, and a big loss at that. Iran’s list of friends is dwindling, and we can be sure that Wen was getting an earful about Tehran from all his new best friends in the Gulf.