WASHINGTON -- In the midst of the presidential campaign last October, Barack Obama's running mate, Joe Biden, warned that within six months of Obama's election, "We're gonna have an international crisis, a generated crisis, to test the mettle of this guy." The prediction hasn't come true yet, but unfriendly nations and international competitors already are stepping up their efforts to challenge the young new president or at the very least get his attention. During the past week, North Korea threatened South Korea and prepared a long-range missile launch. Iran rocketed its first satellite into orbit without outside help. As Taliban...