Jennifer Harris: China preparing to test Trump?

Major geopolitical crises have a way of greeting US presidents soon after taking office. Nazi Germany's withdrawal from the League of Nations in 1933, the Soviet-led construction of the Berlin Wall in 1961, the Gulf of Tonkin incident in 1964 -- all were among the most daunting tests of US foreign policy in the past century, and all came less than a year into the tenures of new US administrations.