The concept of a G-2 was first raised by noted economist C. Fred Bergsten in 2005. In 2009, Bergsten made the following arguments for such a relationship: Zbigniew Brzezinski had been a vocal advocate for the concept. He publicly advanced the notion in Beijing in January 2009 as the two countries celebrated the 30th anniversary of establishing formal diplomatic ties. He views the informal G-2 as helpful in finding solutions to the global financial crisis, climate change, North Korea's nuclear program, Iran's nuclear program, the India–Pakistan tensions, the Israeli–Palestinian conflict, United Nations peacekeeping, nuclear proliferation, and nuclear disarmament. He called the principle of "harmony" a "mission worthy of the two countries with the most extraordinary potential for shaping our collective future". Historian Niall Ferguson has also advocated the G-2 concept. He coined the term Chimerica to describe the symbiotic nature of the U.S.-China economic relationship. Robert Zoellick, former president of the World Bank, and Justin Yifu Lin, the Bank's former chief economist and senior vice president, have stated that the G-2 is crucial for economic recovery and that the U.S. and China must work together. They state that "without a strong G-2, the G-20 will disappoint". While widely discussed, the concept of a G-2 has not been fully defined. According to Brzezinski, G-2 described the current realities, while for former British Foreign SecretaryDavid Miliband, a G-2 could emerge in the foreseeable future. Miliband proposes EU integration as a means to create a potential G-3 that consists of the United States, China and the European Union. Former President Barack Obama and former United StatesSecretary of State Hillary Clinton have been very supportive of good relations between the two countries and more cooperation on more issues more often. Former Secretary of StateHenry Kissinger has stated that U.S.–China relationship to be "taken to a new level". Some experts have disagreed with the effectiveness of a G-2. However, Clinton has said that there is no G-2. The G-2 concept has been often evoked in international media during major bilateral meetings such as the Strategic and Economic Dialogue and state visits as well as during global summits like the G-20 meetings and the Copenhagen Summit.