Iran's apparently clandestine efforts to build a nuclear weapons program are a major foreign policy challenge for the Obama administration. Last year, President Obama challenged the Islamic republic to cease its nuclear program by the end of December or the United States would be forced to consider new economic sanctions. That deadline has come and gone, and yet there is little if any chance that any new sanctions will be imposed in the near term, largely because of China's recalcitrance. On January 5, 2010, China's ambassador to the United Nations effectively foreclosed on U.S. efforts to win UN support for new sanctions, declaring "This is not the right time or right moment for sanctions because diplomatic efforts are still going on." The effective standoff between Washington and...