Russian President Dmitry Medvedev chose the day after Barack Obama's election victory to brandish a threat of ballistic missiles. Venezuelan President Hugo Chavez said of the president-elect: "I hope he doesn't end up being one more imperialist." As for Al-Qaida, it likened Barack Obama, the first black US president, to a favored slave doing his master's bidding. Obama's running mate, Joe Biden, predicted the new president would quickly be tested by a dangerous world. That test might come from anywhere, but attention has focused on North Korea, Iran, Russia and Venezuela, and the al-Qaida terror group. Obama's Republican opponent, John McCain, called him too inexperienced to be president. So did Hillary Clinton, now his choice for secretary of state. Since his election, Obama has filled his national security team with centrists and relative hawks - a possible warning not to underestimate him. "What Obama absolutely must prove early on in his administration is that he cannot be played for a patsy, that he has the strength ... and that he understands his No. 1 duty is as commander in chief and protector of the United States," said Robin Niblett, the director of Chatham House, the London-based think tank.