This year's presidential campaign is shaping up as a major debate on America's foreign policy with stark differences between the most likely candidates. John McCain wants "victory" in Iraq. Barack Obama wants an end—not just to the war, but to what he calls the "mindset" that started it in the first place. Obama wants to talk to America's enemies, while McCain calls that "naive." Those and other stark differences may lead to a history-making debate about America's role in a changing world. Can the US shape global events or is America's super-power dominance in decline? We hear about military power, diplomacy, terrorism and the challenges of globalization.